66640929 has 4 divisors (see below), whose sum is σ = 88854576. Its totient is φ = 44427284.

The previous prime is 66640883. The next prime is 66640943. The reversal of 66640929 is 92904666.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66640929 - 2⁷ = 66640801 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66640229) 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, 11106819 + ... + 11106824.

It is an arithmetic number, because the mean of its divisors is an integer number (22213644).

Almost surely, 2^66640929 is an apocalyptic number.

It is an amenable number.

66640929 is a deficient number, since it is larger than the sum of its proper divisors (22213647).

66640929 is a wasteful number, since it uses less digits than its factorization.

66640929 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22213646.

The product of its (nonzero) digits is 139968, while the sum is 42.

The square root of 66640929 is about 8163.3895533657. The cubic root of 66640929 is about 405.4279457592.

The spelling of 66640929 in words is "sixty-six million, six hundred forty thousand, nine hundred twenty-nine".