57040721 has 2 divisors, whose sum is σ = 57040722. Its totient is φ = 57040720.

The previous prime is 57040693. The next prime is 57040727. The reversal of 57040721 is 12704075.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29593600 + 27447121 = 5440^2 + 5239^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-57040721 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (57040727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28520360 + 28520361.

It is an arithmetic number, because the mean of its divisors is an integer number (28520361).

Almost surely, 2^57040721 is an apocalyptic number.

It is an amenable number.

57040721 is a deficient number, since it is larger than the sum of its proper divisors (1).

57040721 is an equidigital number, since it uses as much as digits as its factorization.

57040721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1960, while the sum is 26.

The square root of 57040721 is about 7552.5307678950. The cubic root of 57040721 is about 384.9417374026.

Adding to 57040721 its reverse (12704075), we get a palindrome (69744796).

The spelling of 57040721 in words is "fifty-seven million, forty thousand, seven hundred twenty-one".