66057981 has 32 divisors (see below), whose sum is σ = 98910720. Its totient is φ = 38875200.

The previous prime is 66057967. The next prime is 66057991. The reversal of 66057981 is 18975066.

It is not a de Polignac number, because 66057981 - 2¹⁴ = 66041597 is a prime.

It is a super-2 number, since 2×66057981² = 8727313707592722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66057961) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 312966 + ... + 313176.

It is an arithmetic number, because the mean of its divisors is an integer number (3090960).

Almost surely, 2^66057981 is an apocalyptic number.

It is an amenable number.

66057981 is a deficient number, since it is larger than the sum of its proper divisors (32852739).

66057981 is a wasteful number, since it uses less digits than its factorization.

66057981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 457.

The product of its (nonzero) digits is 90720, while the sum is 42.

The square root of 66057981 is about 8127.6061051210. The cubic root of 66057981 is about 404.2423084035.

The spelling of 66057981 in words is "sixty-six million, fifty-seven thousand, nine hundred eighty-one".