664721452 has 12 divisors (see below), whose sum is σ = 1163541456. Its totient is φ = 332281040.

The previous prime is 664721419. The next prime is 664721461. The reversal of 664721452 is 254127466.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1377 + ... + 36487.

It is an arithmetic number, because the mean of its divisors is an integer number (96961788).

Almost surely, 2^664721452 is an apocalyptic number.

It is an amenable number.

664721452 is a deficient number, since it is larger than the sum of its proper divisors (498820004).

664721452 is a wasteful number, since it uses less digits than its factorization.

664721452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39848 (or 39846 counting only the distinct ones).

The product of its digits is 80640, while the sum is 37.

The square root of 664721452 is about 25782.1925367103. The cubic root of 664721452 is about 872.7299862513.

The spelling of 664721452 in words is "six hundred sixty-four million, seven hundred twenty-one thousand, four hundred fifty-two".