51392421 has 16 divisors (see below), whose sum is σ = 76852800. Its totient is φ = 33939504.

The previous prime is 51392387. The next prime is 51392447. The reversal of 51392421 is 12429315.

It is not a de Polignac number, because 51392421 - 2⁷ = 51392293 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51392461) 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, 6006 + ... + 11783.

It is an arithmetic number, because the mean of its divisors is an integer number (4803300).

Almost surely, 2^51392421 is an apocalyptic number.

It is an amenable number.

51392421 is a deficient number, since it is larger than the sum of its proper divisors (25460379).

51392421 is a wasteful number, since it uses less digits than its factorization.

51392421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17905 (or 17899 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 51392421 is about 7168.8507447149. The cubic root of 51392421 is about 371.7917018053.

The spelling of 51392421 in words is "fifty-one million, three hundred ninety-two thousand, four hundred twenty-one".