57211721 has 8 divisors (see below), whose sum is σ = 66213120. Its totient is φ = 48417408.

The previous prime is 57211697. The next prime is 57211733. The reversal of 57211721 is 12711275.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 57211721 - 2¹⁸ = 56949577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (57211321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51176 + ... + 52281.

It is an arithmetic number, because the mean of its divisors is an integer number (8276640).

Almost surely, 2^57211721 is an apocalyptic number.

It is an amenable number.

57211721 is a deficient number, since it is larger than the sum of its proper divisors (9001399).

57211721 is a wasteful number, since it uses less digits than its factorization.

57211721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103543.

The product of its digits is 980, while the sum is 26.

The square root of 57211721 is about 7563.8430047166. The cubic root of 57211721 is about 385.3260205792.

Adding to 57211721 its reverse (12711275), we get a palindrome (69922996).

The spelling of 57211721 in words is "fifty-seven million, two hundred eleven thousand, seven hundred twenty-one".