66906810 has 40 divisors (see below), whose sum is σ = 179907156. Its totient is φ = 17841600.

The previous prime is 66906797. The next prime is 66906821. The reversal of 66906810 is 1860966.

It can be written as a sum of positive squares in 2 ways, for example, as 64593369 + 2313441 = 8037^2 + 1521^2 .

It is a super-2 number, since 2×66906810² = 8953042448752200, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 40491 + ... + 42110.

Almost surely, 2^66906810 is an apocalyptic number.

66906810 is an abundant number, since it is smaller than the sum of its proper divisors (113000346).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66906810 is a wasteful number, since it uses less digits than its factorization.

66906810 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82620 (or 82611 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 66906810 is about 8179.6583058218. The cubic root of 66906810 is about 405.9664163700.

The spelling of 66906810 in words is "sixty-six million, nine hundred six thousand, eight hundred ten".