61217540 has 24 divisors (see below), whose sum is σ = 128871960. Its totient is φ = 24427008.

The previous prime is 61217539. The next prime is 61217543. The reversal of 61217540 is 4571216.

It can be written as a sum of positive squares in 4 ways, for example, as 33856 + 61183684 = 184^2 + 7822^2 .

It is not an unprimeable number, because it can be changed into a prime (61217543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5126 + ... + 12194.

It is an arithmetic number, because the mean of its divisors is an integer number (5369665).

Almost surely, 2^61217540 is an apocalyptic number.

It is an amenable number.

61217540 is an abundant number, since it is smaller than the sum of its proper divisors (67654420).

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

61217540 is a wasteful number, since it uses less digits than its factorization.

61217540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7511 (or 7509 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 61217540 is about 7824.1638530900. The cubic root of 61217540 is about 394.1171115530.

Adding to 61217540 its reverse (4571216), we get a palindrome (65788756).

The spelling of 61217540 in words is "sixty-one million, two hundred seventeen thousand, five hundred forty".