61640400 has 120 divisors (see below), whose sum is σ = 203947264. Its totient is φ = 15897600.

The previous prime is 61640393. The next prime is 61640407. The reversal of 61640400 is 404616.

61640400 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 (61640393) and next prime (61640407).

It is a tau number, because it is divible by the number of its divisors (120).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61640407) 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 23 ways as a sum of consecutive naturals, for example, 36372 + ... + 38028.

Almost surely, 2^61640400 is an apocalyptic number.

61640400 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61640400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101973632).

61640400 is an abundant number, since it is smaller than the sum of its proper divisors (142306864).

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

61640400 is a wasteful number, since it uses less digits than its factorization.

61640400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1709 (or 1698 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 61640400 is about 7851.1400446050. The cubic root of 61640400 is about 395.0224844329.

The spelling of 61640400 in words is "sixty-one million, six hundred forty thousand, four hundred".