51724321 has 4 divisors (see below), whose sum is σ = 56426544. Its totient is φ = 47022100.

The previous prime is 51724303. The next prime is 51724331. The reversal of 51724321 is 12342715.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 51724321 - 2¹¹ = 51722273 is a prime.

It is a super-2 number, since 2×51724321² = 5350810765822082, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51724331) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2351095 + ... + 2351116.

It is an arithmetic number, because the mean of its divisors is an integer number (14106636).

Almost surely, 2^51724321 is an apocalyptic number.

It is an amenable number.

51724321 is a deficient number, since it is larger than the sum of its proper divisors (4702223).

51724321 is a wasteful number, since it uses less digits than its factorization.

51724321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4702222.

The product of its digits is 1680, while the sum is 25.

The square root of 51724321 is about 7191.9622496228. The cubic root of 51724321 is about 372.5903472877.

The spelling of 51724321 in words is "fifty-one million, seven hundred twenty-four thousand, three hundred twenty-one".