66999710 has 16 divisors (see below), whose sum is σ = 120724992. Its totient is φ = 26772000.

The previous prime is 66999707. The next prime is 66999721. The reversal of 66999710 is 1799966.

It is a happy number.

It is a super-2 number, since 2×66999710² = 8977922280168200, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8600 + ... + 14420.

It is an arithmetic number, because the mean of its divisors is an integer number (7545312).

Almost surely, 2^66999710 is an apocalyptic number.

66999710 is a deficient number, since it is larger than the sum of its proper divisors (53725282).

66999710 is a wasteful number, since it uses less digits than its factorization.

66999710 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6979.

The product of its (nonzero) digits is 183708, while the sum is 47.

The square root of 66999710 is about 8185.3350572838. The cubic root of 66999710 is about 406.1542240492.

The spelling of 66999710 in words is "sixty-six million, nine hundred ninety-nine thousand, seven hundred ten".