21701921421 has 32 divisors (see below), whose sum is σ = 31384679040. Its totient is φ = 13285730304.

The previous prime is 21701921413. The next prime is 21701921459. The reversal of 21701921421 is 12412910712.

It is not a de Polignac number, because 21701921421 - 2³ = 21701921413 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21701921491) 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, 2216625 + ... + 2226393.

It is an arithmetic number, because the mean of its divisors is an integer number (980771220).

Almost surely, 2^21701921421 is an apocalyptic number.

It is an amenable number.

21701921421 is a deficient number, since it is larger than the sum of its proper divisors (9682757619).

21701921421 is a wasteful number, since it uses less digits than its factorization.

21701921421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10845.

The product of its (nonzero) digits is 2016, while the sum is 30.

The spelling of 21701921421 in words is "twenty-one billion, seven hundred one million, nine hundred twenty-one thousand, four hundred twenty-one".