66991024 has 20 divisors (see below), whose sum is σ = 130080960. Its totient is φ = 33421760.

The previous prime is 66991021. The next prime is 66991037. The reversal of 66991024 is 42019966.

It is not an unprimeable number, because it can be changed into a prime (66991021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3294 + ... + 12034.

It is an arithmetic number, because the mean of its divisors is an integer number (6504048).

Almost surely, 2^66991024 is an apocalyptic number.

It is an amenable number.

66991024 is a deficient number, since it is larger than the sum of its proper divisors (63089936).

66991024 is a wasteful number, since it uses less digits than its factorization.

66991024 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9228 (or 9222 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 37.

The square root of 66991024 is about 8184.8044570411. The cubic root of 66991024 is about 406.1366716944.

The spelling of 66991024 in words is "sixty-six million, nine hundred ninety-one thousand, twenty-four".