51398021 has 16 divisors (see below), whose sum is σ = 57620160. Its totient is φ = 45561600.

The previous prime is 51398003. The next prime is 51398033. The reversal of 51398021 is 12089315.

It is a cyclic number.

It is not a de Polignac number, because 51398021 - 2¹⁴ = 51381637 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51398041) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 72971 + ... + 73671.

It is an arithmetic number, because the mean of its divisors is an integer number (3601260).

Almost surely, 2^51398021 is an apocalyptic number.

It is an amenable number.

51398021 is a deficient number, since it is larger than the sum of its proper divisors (6222139).

51398021 is a wasteful number, since it uses less digits than its factorization.

51398021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 964.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 51398021 is about 7169.2413127192. The cubic root of 51398021 is about 371.8052054690.

The spelling of 51398021 in words is "fifty-one million, three hundred ninety-eight thousand, twenty-one".