57061981 has 2 divisors, whose sum is σ = 57061982. Its totient is φ = 57061980.

The previous prime is 57061951. The next prime is 57061987. The reversal of 57061981 is 18916075.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 56475225 + 586756 = 7515^2 + 766^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-57061981 is a prime.

It is a super-2 number, since 2×57061981² = 6512139351288722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 57061981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (57061987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28530990 + 28530991.

It is an arithmetic number, because the mean of its divisors is an integer number (28530991).

Almost surely, 2^57061981 is an apocalyptic number.

It is an amenable number.

57061981 is a deficient number, since it is larger than the sum of its proper divisors (1).

57061981 is an equidigital number, since it uses as much as digits as its factorization.

57061981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15120, while the sum is 37.

The square root of 57061981 is about 7553.9381120049. The cubic root of 57061981 is about 384.9895561343.

The spelling of 57061981 in words is "fifty-seven million, sixty-one thousand, nine hundred eighty-one".