66816280 has 16 divisors (see below), whose sum is σ = 150336720. Its totient is φ = 26726496.

The previous prime is 66816271. The next prime is 66816283. The reversal of 66816280 is 8261866.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66816283) 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, 835164 + ... + 835243.

It is an arithmetic number, because the mean of its divisors is an integer number (9396045).

Almost surely, 2^66816280 is an apocalyptic number.

It is an amenable number.

66816280 is an abundant number, since it is smaller than the sum of its proper divisors (83520440).

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

66816280 is a wasteful number, since it uses less digits than its factorization.

66816280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1670418 (or 1670414 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 37.

The square root of 66816280 is about 8174.1225828831. The cubic root of 66816280 is about 405.7832325840.

The spelling of 66816280 in words is "sixty-six million, eight hundred sixteen thousand, two hundred eighty".