20787757477566 has 16 divisors (see below), whose sum is σ = 41987153718288. Its totient is φ = 6860646032000.

The previous prime is 20787757477537. The next prime is 20787757477573. The reversal of 20787757477566 is 66577475778702.

It is a super-2 number, since 2×20787757477566² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20787757477491 and 20787757477500.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17151614475 + ... + 17151615686.

It is an arithmetic number, because the mean of its divisors is an integer number (2624197107393).

Almost surely, 2^{20787757477566} is an apocalyptic number.

20787757477566 is an abundant number, since it is smaller than the sum of its proper divisors (21199396240722).

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

20787757477566 is a wasteful number, since it uses less digits than its factorization.

20787757477566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34303230267.

The product of its (nonzero) digits is 6776582400, while the sum is 78.

The spelling of 20787757477566 in words is "twenty trillion, seven hundred eighty-seven billion, seven hundred fifty-seven million, four hundred seventy-seven thousand, five hundred sixty-six".