61388931 has 16 divisors (see below), whose sum is σ = 84153888. Its totient is φ = 39782400.

The previous prime is 61388903. The next prime is 61388941. The reversal of 61388931 is 13988316.

It is a de Polignac number, because none of the positive numbers 2^k-61388931 is a prime.

It is a super-2 number, since 2×61388931² = 7537201698645522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 61388931.

It is not an unprimeable number, because it can be changed into a prime (61388941) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40711 + ... + 42191.

It is an arithmetic number, because the mean of its divisors is an integer number (5259618).

Almost surely, 2^61388931 is an apocalyptic number.

61388931 is a deficient number, since it is larger than the sum of its proper divisors (22764957).

61388931 is a wasteful number, since it uses less digits than its factorization.

61388931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1862.

The product of its digits is 31104, while the sum is 39.

The square root of 61388931 is about 7835.1088696967. The cubic root of 61388931 is about 394.4845726079.

The spelling of 61388931 in words is "sixty-one million, three hundred eighty-eight thousand, nine hundred thirty-one".