66801555 has 12 divisors (see below), whose sum is σ = 115789440. Its totient is φ = 35627472.

The previous prime is 66801533. The next prime is 66801563. The reversal of 66801555 is 55510866.

It is not a de Polignac number, because 66801555 - 2²³ = 58412947 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 742195 + ... + 742284.

It is an arithmetic number, because the mean of its divisors is an integer number (9649120).

Almost surely, 2^66801555 is an apocalyptic number.

66801555 is a deficient number, since it is larger than the sum of its proper divisors (48987885).

66801555 is a wasteful number, since it uses less digits than its factorization.

66801555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1484490 (or 1484487 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 36.

The square root of 66801555 is about 8173.2218249598. The cubic root of 66801555 is about 405.7534215006.

The spelling of 66801555 in words is "sixty-six million, eight hundred one thousand, five hundred fifty-five".