21786337764 has 36 divisors (see below), whose sum is σ = 57969497040. Its totient is φ = 6879895920.

The previous prime is 21786337757. The next prime is 21786337787. The reversal of 21786337764 is 46773368712.

It is a tau number, because it is divible by the number of its divisors (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21786337764.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15925002 + ... + 15926369.

Almost surely, 2^21786337764 is an apocalyptic number.

It is an amenable number.

21786337764 is an abundant number, since it is smaller than the sum of its proper divisors (36183159276).

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

21786337764 is a wasteful number, since it uses less digits than its factorization.

21786337764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31851400 (or 31851395 counting only the distinct ones).

The product of its digits is 7112448, while the sum is 54.

The spelling of 21786337764 in words is "twenty-one billion, seven hundred eighty-six million, three hundred thirty-seven thousand, seven hundred sixty-four".