21786164708 has 96 divisors (see below), whose sum is σ = 48314155008. Its totient is φ = 8419451040.

The previous prime is 21786164707. The next prime is 21786164737. The reversal of 21786164708 is 80746168712.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21786164707) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4730735 + ... + 4735337.

It is an arithmetic number, because the mean of its divisors is an integer number (503272448).

Almost surely, 2^21786164708 is an apocalyptic number.

21786164708 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21786164708, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24157077504).

21786164708 is an abundant number, since it is smaller than the sum of its proper divisors (26527990300).

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

21786164708 is a wasteful number, since it uses less digits than its factorization.

21786164708 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4774 (or 4750 counting only the distinct ones).

The product of its (nonzero) digits is 903168, while the sum is 50.

The spelling of 21786164708 in words is "twenty-one billion, seven hundred eighty-six million, one hundred sixty-four thousand, seven hundred eight".