21077104101556 has 6 divisors (see below), whose sum is σ = 36884932177730. Its totient is φ = 10538552050776.

The previous prime is 21077104101503. The next prime is 21077104101587. The reversal of 21077104101556 is 65510140177012.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 12750012752656 + 8327091348900 = 3570716^2 + 2885670^2 .

It is a super-2 number, since 2×21077104101556² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2634638012691 + ... + 2634638012698.

Almost surely, 2^{21077104101556} is an apocalyptic number.

It is an amenable number.

21077104101556 is a deficient number, since it is larger than the sum of its proper divisors (15807828076174).

21077104101556 is a wasteful number, since it uses less digits than its factorization.

21077104101556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5269276025393 (or 5269276025391 counting only the distinct ones).

The product of its (nonzero) digits is 58800, while the sum is 40.

Adding to 21077104101556 its reverse (65510140177012), we get a palindrome (86587244278568).

The spelling of 21077104101556 in words is "twenty-one trillion, seventy-seven billion, one hundred four million, one hundred one thousand, five hundred fifty-six".