21377072655 has 24 divisors (see below), whose sum is σ = 37280928048. Its totient is φ = 11331156096.

The previous prime is 21377072621. The next prime is 21377072663. The reversal of 21377072655 is 55627077312.

It is not a de Polignac number, because 21377072655 - 2¹¹ = 21377070607 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 21377072655.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1449862 + ... + 1464531.

It is an arithmetic number, because the mean of its divisors is an integer number (1553372002).

Almost surely, 2^21377072655 is an apocalyptic number.

21377072655 is a deficient number, since it is larger than the sum of its proper divisors (15903855393).

21377072655 is a wasteful number, since it uses less digits than its factorization.

21377072655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2914567 (or 2914564 counting only the distinct ones).

The product of its (nonzero) digits is 617400, while the sum is 45.

The spelling of 21377072655 in words is "twenty-one billion, three hundred seventy-seven million, seventy-two thousand, six hundred fifty-five".