66745664 has 14 divisors (see below), whose sum is σ = 132448554. Its totient is φ = 33372800.

The previous prime is 66745633. The next prime is 66745667. The reversal of 66745664 is 46654766.

It can be written as a sum of positive squares in only one way, i.e., 65286400 + 1459264 = 8080^2 + 1208^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66745667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 521387 + ... + 521514.

It is an arithmetic number, because the mean of its divisors is an integer number (9460611).

Almost surely, 2^66745664 is an apocalyptic number.

66745664 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

66745664 is a deficient number, since it is larger than the sum of its proper divisors (65702890).

66745664 is a wasteful number, since it uses less digits than its factorization.

66745664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1042913 (or 1042903 counting only the distinct ones).

The product of its digits is 725760, while the sum is 44.

The square root of 66745664 is about 8169.8019559840. The cubic root of 66745664 is about 405.6402290652.

The spelling of 66745664 in words is "sixty-six million, seven hundred forty-five thousand, six hundred sixty-four".