57238721 has 4 divisors (see below), whose sum is σ = 59212500. Its totient is φ = 55264944.

The previous prime is 57238717. The next prime is 57238729. The reversal of 57238721 is 12783275.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17106496 + 40132225 = 4136^2 + 6335^2 .

It is a cyclic number.

It is not a de Polignac number, because 57238721 - 2² = 57238717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (57238729) 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, 986846 + ... + 986903.

It is an arithmetic number, because the mean of its divisors is an integer number (14803125).

Almost surely, 2^57238721 is an apocalyptic number.

It is an amenable number.

57238721 is a deficient number, since it is larger than the sum of its proper divisors (1973779).

57238721 is a wasteful number, since it uses less digits than its factorization.

57238721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1973778.

The product of its digits is 23520, while the sum is 35.

The square root of 57238721 is about 7565.6276011974. The cubic root of 57238721 is about 385.3866268453.

It can be divided in two parts, 572 and 38721, that added together give a palindrome (39293).

The spelling of 57238721 in words is "fifty-seven million, two hundred thirty-eight thousand, seven hundred twenty-one".