21177723516 has 24 divisors (see below), whose sum is σ = 50110671744. Its totient is φ = 6959814960.

The previous prime is 21177723433. The next prime is 21177723533. The reversal of 21177723516 is 61532777112.

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 7 ways as a sum of consecutive naturals, for example, 12427390 + ... + 12429093.

It is an arithmetic number, because the mean of its divisors is an integer number (2087944656).

Almost surely, 2^21177723516 is an apocalyptic number.

It is an amenable number.

21177723516 is an abundant number, since it is smaller than the sum of its proper divisors (28932948228).

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

21177723516 is a wasteful number, since it uses less digits than its factorization.

21177723516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24856561 (or 24856559 counting only the distinct ones).

The product of its digits is 123480, while the sum is 42.

The spelling of 21177723516 in words is "twenty-one billion, one hundred seventy-seven million, seven hundred twenty-three thousand, five hundred sixteen".