66581725 has 24 divisors (see below), whose sum is σ = 95315328. Its totient is φ = 45192000.

The previous prime is 66581717. The next prime is 66581737. The reversal of 66581725 is 52718566.

It is not a de Polignac number, because 66581725 - 2³ = 66581717 is a prime.

It is a super-2 number, since 2×66581725² = 8866252207951250, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15792 + ... + 19558.

It is an arithmetic number, because the mean of its divisors is an integer number (3971472).

Almost surely, 2^66581725 is an apocalyptic number.

It is an amenable number.

66581725 is a deficient number, since it is larger than the sum of its proper divisors (28733603).

66581725 is a wasteful number, since it uses less digits than its factorization.

66581725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3885 (or 3880 counting only the distinct ones).

The product of its digits is 100800, while the sum is 40.

The square root of 66581725 is about 8159.7625578199. The cubic root of 66581725 is about 405.3078490556.

The spelling of 66581725 in words is "sixty-six million, five hundred eighty-one thousand, seven hundred twenty-five".