61638879725 has 24 divisors (see below), whose sum is σ = 77752821120. Its totient is φ = 48459640320.

The previous prime is 61638879721. The next prime is 61638879749. The reversal of 61638879725 is 52797883616.

It is not a de Polignac number, because 61638879725 - 2² = 61638879721 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61638879721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7050557 + ... + 7059293.

It is an arithmetic number, because the mean of its divisors is an integer number (3239700880).

Almost surely, 2^61638879725 is an apocalyptic number.

It is an amenable number.

61638879725 is a deficient number, since it is larger than the sum of its proper divisors (16113941395).

61638879725 is a wasteful number, since it uses less digits than its factorization.

61638879725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13589 (or 13584 counting only the distinct ones).

The product of its digits is 30481920, while the sum is 62.

It can be divided in two parts, 6163 and 8879725, that added together give a palindrome (8885888).

The spelling of 61638879725 in words is "sixty-one billion, six hundred thirty-eight million, eight hundred seventy-nine thousand, seven hundred twenty-five".