36665721 has 24 divisors (see below), whose sum is σ = 53992224. Its totient is φ = 23974080.

The previous prime is 36665711. The next prime is 36665737. The reversal of 36665721 is 12756663.

It is not a de Polignac number, because 36665721 - 2⁵ = 36665689 is a prime.

It is a super-3 number, since 3×36665721³ (a number of 24 digits) contains 333 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (36665711) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 161410 + ... + 161636.

It is an arithmetic number, because the mean of its divisors is an integer number (2249676).

Almost surely, 2^36665721 is an apocalyptic number.

It is an amenable number.

36665721 is a deficient number, since it is larger than the sum of its proper divisors (17326503).

36665721 is a wasteful number, since it uses less digits than its factorization.

36665721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 501 (or 498 counting only the distinct ones).

The product of its digits is 45360, while the sum is 36.

The square root of 36665721 is about 6055.2226218365. Note that the first 3 decimals coincide. The cubic root of 36665721 is about 332.2156417073.

The spelling of 36665721 in words is "thirty-six million, six hundred sixty-five thousand, seven hundred twenty-one".