66856634 has 8 divisors (see below), whose sum is σ = 107999220. Its totient is φ = 30856896.

The previous prime is 66856633. The next prime is 66856639. The reversal of 66856634 is 43665866.

It can be written as a sum of positive squares in 2 ways, for example, as 66373609 + 483025 = 8147^2 + 695^2 .

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66856633) 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, 1285679 + ... + 1285730.

Almost surely, 2^66856634 is an apocalyptic number.

66856634 is a deficient number, since it is larger than the sum of its proper divisors (41142586).

66856634 is a wasteful number, since it uses less digits than its factorization.

66856634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2571424.

The product of its digits is 622080, while the sum is 44.

The square root of 66856634 is about 8176.5906097835. The cubic root of 66856634 is about 405.8649076942.

The spelling of 66856634 in words is "sixty-six million, eight hundred fifty-six thousand, six hundred thirty-four".