661321372 has 24 divisors (see below), whose sum is σ = 1219111040. Its totient is φ = 313029360.

The previous prime is 661321361. The next prime is 661321373. The reversal of 661321372 is 273123166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661321373) 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, 150673 + ... + 154999.

Almost surely, 2^661321372 is an apocalyptic number.

It is an amenable number.

661321372 is a deficient number, since it is larger than the sum of its proper divisors (557789668).

661321372 is a wasteful number, since it uses less digits than its factorization.

661321372 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6361 (or 6359 counting only the distinct ones).

The product of its digits is 9072, while the sum is 31.

The square root of 661321372 is about 25716.1694659216. The cubic root of 661321372 is about 871.2394242682.

The spelling of 661321372 in words is "six hundred sixty-one million, three hundred twenty-one thousand, three hundred seventy-two".