57432721 has 4 divisors (see below), whose sum is σ = 57448000. Its totient is φ = 57417444.

The previous prime is 57432703. The next prime is 57432737. The reversal of 57432721 is 12723475.

57432721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 57432721 - 2⁵ = 57432689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (57432751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2380 + ... + 10978.

It is an arithmetic number, because the mean of its divisors is an integer number (14362000).

Almost surely, 2^57432721 is an apocalyptic number.

It is an amenable number.

57432721 is a deficient number, since it is larger than the sum of its proper divisors (15279).

57432721 is an equidigital number, since it uses as much as digits as its factorization.

57432721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15278.

The product of its digits is 11760, while the sum is 31.

The square root of 57432721 is about 7578.4378997258. The cubic root of 57432721 is about 385.8215346352.

It can be divided in two parts, 5743 and 2721, that added together give a square (8464 = 92²).

The spelling of 57432721 in words is "fifty-seven million, four hundred thirty-two thousand, seven hundred twenty-one".