61639936 has 54 divisors (see below), whose sum is σ = 126865970. Its totient is φ = 29887488.

The previous prime is 61639843. The next prime is 61639937. The reversal of 61639936 is 63993616.

It can be written as a sum of positive squares in only one way, i.e., 56550400 + 5089536 = 7520^2 + 2256^2 .

It is a junction number, because it is equal to n+sod(n) for n = 61639892 and 61639901.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61639937) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 565450 + ... + 565558.

Almost surely, 2^61639936 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61639936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (63432985).

61639936 is an abundant number, since it is smaller than the sum of its proper divisors (65226034).

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

61639936 is an equidigital number, since it uses as much as digits as its factorization.

61639936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219 (or 158 counting only the distinct ones).

The product of its digits is 157464, while the sum is 43.

The square root of 61639936 is about 7851.1104947007. The cubic root of 61639936 is about 395.0214932491.

The spelling of 61639936 in words is "sixty-one million, six hundred thirty-nine thousand, nine hundred thirty-six".