66904013 has 4 divisors (see below), whose sum is σ = 72986208. Its totient is φ = 60821820.

The previous prime is 66904003. The next prime is 66904031. The reversal of 66904013 is 31040966.

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 66904013 - 2¹⁰ = 66902989 is a prime.

It is a super-2 number, since 2×66904013² = 8952293911008338, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66904003) 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, 3041081 + ... + 3041102.

It is an arithmetic number, because the mean of its divisors is an integer number (18246552).

Almost surely, 2^66904013 is an apocalyptic number.

It is an amenable number.

66904013 is a deficient number, since it is larger than the sum of its proper divisors (6082195).

66904013 is a wasteful number, since it uses less digits than its factorization.

66904013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6082194.

The product of its (nonzero) digits is 3888, while the sum is 29.

The square root of 66904013 is about 8179.4873311229. The cubic root of 66904013 is about 405.9607592284.

Adding to 66904013 its reverse (31040966), we get a palindrome (97944979).

The spelling of 66904013 in words is "sixty-six million, nine hundred four thousand, thirteen".