66278564 has 24 divisors (see below), whose sum is σ = 126741888. Its totient is φ = 30076640.

The previous prime is 66278561. The next prime is 66278573. The reversal of 66278564 is 46587266.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is not an unprimeable number, because it can be changed into a prime (66278561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43829 + ... + 45315.

It is an arithmetic number, because the mean of its divisors is an integer number (5280912).

Almost surely, 2^66278564 is an apocalyptic number.

It is an amenable number.

66278564 is a deficient number, since it is larger than the sum of its proper divisors (60463324).

66278564 is a wasteful number, since it uses less digits than its factorization.

66278564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2515 (or 2513 counting only the distinct ones).

The product of its digits is 483840, while the sum is 44.

The square root of 66278564 is about 8141.1647815285. The cubic root of 66278564 is about 404.6917616035.

The spelling of 66278564 in words is "sixty-six million, two hundred seventy-eight thousand, five hundred sixty-four".