21064625421 has 32 divisors (see below), whose sum is σ = 34018403328. Its totient is φ = 11318280960.

The previous prime is 21064625419. The next prime is 21064625423. The reversal of 21064625421 is 12452646012.

It is an interprime number because it is at equal distance from previous prime (21064625419) and next prime (21064625423).

It is not a de Polignac number, because 21064625421 - 2¹ = 21064625419 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21064625423) 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, 362446 + ... + 416528.

It is an arithmetic number, because the mean of its divisors is an integer number (1063075104).

Almost surely, 2^21064625421 is an apocalyptic number.

21064625421 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21064625421 is a deficient number, since it is larger than the sum of its proper divisors (12953777907).

21064625421 is a wasteful number, since it uses less digits than its factorization.

21064625421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55201.

The product of its (nonzero) digits is 23040, while the sum is 33.

The spelling of 21064625421 in words is "twenty-one billion, sixty-four million, six hundred twenty-five thousand, four hundred twenty-one".