61817940 has 36 divisors (see below), whose sum is σ = 187514964. Its totient is φ = 16484736.

The previous prime is 61817939. The next prime is 61817941. The reversal of 61817940 is 4971816.

61817940 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (61817939) and next prime (61817941).

It can be written as a sum of positive squares in 2 ways, for example, as 10150596 + 51667344 = 3186^2 + 7188^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 61817895 and 61817904.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61817941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 171537 + ... + 171896.

It is an arithmetic number, because the mean of its divisors is an integer number (5208749).

Almost surely, 2^61817940 is an apocalyptic number.

61817940 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

61817940 is an abundant number, since it is smaller than the sum of its proper divisors (125697024).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

61817940 is a wasteful number, since it uses less digits than its factorization.

61817940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 343448 (or 343443 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 36.

The square root of 61817940 is about 7862.4385530190. The cubic root of 61817940 is about 395.4013759093.

The spelling of 61817940 in words is "sixty-one million, eight hundred seventeen thousand, nine hundred forty".