66381975 has 36 divisors (see below), whose sum is σ = 129711192. Its totient is φ = 32184000.

The previous prime is 66381967. The next prime is 66382007. The reversal of 66381975 is 57918366.

It is a happy number.

66381975 is a `hidden beast` number, since 6 + 638 + 1 + 9 + 7 + 5 = 666.

It is not a de Polignac number, because 66381975 - 2³ = 66381967 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 66381975.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 10936 + ... + 15885.

Almost surely, 2^66381975 is an apocalyptic number.

66381975 is a deficient number, since it is larger than the sum of its proper divisors (63329217).

66381975 is a wasteful number, since it uses less digits than its factorization.

66381975 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26848 (or 26840 counting only the distinct ones).

The product of its digits is 272160, while the sum is 45.

The square root of 66381975 is about 8147.5134243522. The cubic root of 66381975 is about 404.9021254116.

The spelling of 66381975 in words is "sixty-six million, three hundred eighty-one thousand, nine hundred seventy-five".