66691610 has 8 divisors (see below), whose sum is σ = 120044916. Its totient is φ = 26676640.

The previous prime is 66691609. The next prime is 66691621. The reversal of 66691610 is 1619666.

It can be written as a sum of positive squares in 2 ways, for example, as 66308449 + 383161 = 8143^2 + 619^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3334571 + ... + 3334590.

Almost surely, 2^66691610 is an apocalyptic number.

66691610 is a deficient number, since it is larger than the sum of its proper divisors (53353306).

66691610 is a wasteful number, since it uses less digits than its factorization.

66691610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6669168.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 66691610 is about 8166.4931274079. The cubic root of 66691610 is about 405.5306968632.

The spelling of 66691610 in words is "sixty-six million, six hundred ninety-one thousand, six hundred ten".