21421707744 has 24 divisors (see below), whose sum is σ = 56231983080. Its totient is φ = 7140569216.

The previous prime is 21421707743. The next prime is 21421707751. The reversal of 21421707744 is 44770712412.

It is a tau number, because it is divible by the number of its divisors (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421707743) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 111571299 + ... + 111571490.

It is an arithmetic number, because the mean of its divisors is an integer number (2342999295).

Almost surely, 2^21421707744 is an apocalyptic number.

21421707744 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21421707744 is an abundant number, since it is smaller than the sum of its proper divisors (34810275336).

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

21421707744 is a wasteful number, since it uses less digits than its factorization.

21421707744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223142802 (or 223142794 counting only the distinct ones).

The product of its (nonzero) digits is 87808, while the sum is 39.

The spelling of 21421707744 in words is "twenty-one billion, four hundred twenty-one million, seven hundred seven thousand, seven hundred forty-four".