65166021 has 6 divisors (see below), whose sum is σ = 94128710. Its totient is φ = 43444008.

The previous prime is 65165951. The next prime is 65166037. The reversal of 65166021 is 12066156.

It is a happy number.

65166021 is a `hidden beast` number, since 6 + 51 + 6 + 602 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 47196900 + 17969121 = 6870^2 + 4239^2 .

It is a de Polignac number, because none of the positive numbers 2^k-65166021 is a prime.

It is a super-2 number, since 2×65166021² = 8493220585944882, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65166071) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3620326 + ... + 3620343.

Almost surely, 2^65166021 is an apocalyptic number.

It is an amenable number.

65166021 is a deficient number, since it is larger than the sum of its proper divisors (28962689).

65166021 is a wasteful number, since it uses less digits than its factorization.

65166021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7240675 (or 7240672 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 65166021 is about 8072.5473674671. The cubic root of 65166021 is about 402.4146052909.

The spelling of 65166021 in words is "sixty-five million, one hundred sixty-six thousand, twenty-one".