21640401421 has 8 divisors (see below), whose sum is σ = 21757824000. Its totient is φ = 21523022160.

The previous prime is 21640401403. The next prime is 21640401463. The reversal of 21640401421 is 12410404612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21640401421 - 2²⁹ = 21103530509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21640401521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1779600 + ... + 1791718.

It is an arithmetic number, because the mean of its divisors is an integer number (2719728000).

Almost surely, 2^21640401421 is an apocalyptic number.

It is an amenable number.

21640401421 is a deficient number, since it is larger than the sum of its proper divisors (117422579).

21640401421 is a wasteful number, since it uses less digits than its factorization.

21640401421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21659.

The product of its (nonzero) digits is 1536, while the sum is 25.

The spelling of 21640401421 in words is "twenty-one billion, six hundred forty million, four hundred one thousand, four hundred twenty-one".