61139664 has 80 divisors (see below), whose sum is σ = 176447040. Its totient is φ = 20269440.

The previous prime is 61139653. The next prime is 61139671. The reversal of 61139664 is 46693116.

61139664 is a `hidden beast` number, since 611 + 39 + 6 + 6 + 4 = 666.

61139664 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 132394 + ... + 132854.

It is an arithmetic number, because the mean of its divisors is an integer number (2205588).

Almost surely, 2^61139664 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 61139664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88223520).

61139664 is an abundant number, since it is smaller than the sum of its proper divisors (115307376).

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

61139664 is a wasteful number, since it uses less digits than its factorization.

61139664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 785 (or 773 counting only the distinct ones).

The product of its digits is 23328, while the sum is 36.

The square root of 61139664 is about 7819.1856353459. The cubic root of 61139664 is about 393.9499193391.

The spelling of 61139664 in words is "sixty-one million, one hundred thirty-nine thousand, six hundred sixty-four".