51573721 has 2 divisors, whose sum is σ = 51573722. Its totient is φ = 51573720.

The previous prime is 51573707. The next prime is 51573749. The reversal of 51573721 is 12737515.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50965321 + 608400 = 7139^2 + 780^2 .

It is a cyclic number.

It is not a de Polignac number, because 51573721 - 2⁷ = 51573593 is a prime.

It is not a weakly prime, because it can be changed into another prime (51573791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25786860 + 25786861.

It is an arithmetic number, because the mean of its divisors is an integer number (25786861).

Almost surely, 2^51573721 is an apocalyptic number.

It is an amenable number.

51573721 is a deficient number, since it is larger than the sum of its proper divisors (1).

51573721 is an equidigital number, since it uses as much as digits as its factorization.

51573721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7350, while the sum is 31.

The square root of 51573721 is about 7181.4845958200. The cubic root of 51573721 is about 372.2283856937.

The spelling of 51573721 in words is "fifty-one million, five hundred seventy-three thousand, seven hundred twenty-one".