661623328 has 24 divisors (see below), whose sum is σ = 1344591360. Its totient is φ = 320139840.

The previous prime is 661623283. The next prime is 661623329. The reversal of 661623328 is 823326166.

It is not an unprimeable number, because it can be changed into a prime (661623329) 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, 332488 + ... + 334471.

It is an arithmetic number, because the mean of its divisors is an integer number (56024640).

Almost surely, 2^661623328 is an apocalyptic number.

It is an amenable number.

661623328 is an abundant number, since it is smaller than the sum of its proper divisors (682968032).

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

661623328 is a wasteful number, since it uses less digits than its factorization.

661623328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 667000 (or 666992 counting only the distinct ones).

The product of its digits is 62208, while the sum is 37.

The square root of 661623328 is about 25722.0397324940. The cubic root of 661623328 is about 871.3720052659.

The spelling of 661623328 in words is "six hundred sixty-one million, six hundred twenty-three thousand, three hundred twenty-eight".