61657617777021 has 80 divisors (see below), whose sum is σ = 106793990392320. Its totient is φ = 34723792696320.

The previous prime is 61657617777011. The next prime is 61657617777109. The reversal of 61657617777021 is 12077771675616.

61657617777021 is a `hidden beast` number, since 6 + 1 + 6 + 5 + 7 + 617 + 7 + 7 + 7 + 0 + 2 + 1 = 666.

61657617777021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 61657617777021 - 2³⁴ = 61640437907837 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a self number, because there is not a number n which added to its sum of digits gives 61657617777021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61657617777011) 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 79 ways as a sum of consecutive naturals, for example, 10799431 + ... + 15490091.

It is an arithmetic number, because the mean of its divisors is an integer number (1334924879904).

Almost surely, 2^{61657617777021} is an apocalyptic number.

It is an amenable number.

61657617777021 is a deficient number, since it is larger than the sum of its proper divisors (45136372615299).

61657617777021 is a wasteful number, since it uses less digits than its factorization.

61657617777021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4691016 (or 4691007 counting only the distinct ones).

The product of its (nonzero) digits is 36303120, while the sum is 63.

The spelling of 61657617777021 in words is "sixty-one trillion, six hundred fifty-seven billion, six hundred seventeen million, seven hundred seventy-seven thousand, twenty-one".