21492311064 has 128 divisors (see below), whose sum is σ = 66776348160. Its totient is φ = 5623216128.

The previous prime is 21492311063. The next prime is 21492311131. The reversal of 21492311064 is 46011329412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21492311063) 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, 3979 + ... + 207365.

It is an arithmetic number, because the mean of its divisors is an integer number (521690220).

Almost surely, 2^21492311064 is an apocalyptic number.

21492311064 is a gapful number since it is divisible by the number (24) 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 21492311064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33388174080).

21492311064 is an abundant number, since it is smaller than the sum of its proper divisors (45284037096).

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

21492311064 is a wasteful number, since it uses less digits than its factorization.

21492311064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203457 (or 203453 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 33.

The spelling of 21492311064 in words is "twenty-one billion, four hundred ninety-two million, three hundred eleven thousand, sixty-four".