661320356 has 12 divisors (see below), whose sum is σ = 1159114992. Its totient is φ = 330144648.

The previous prime is 661320307. The next prime is 661320377. The reversal of 661320356 is 653023166.

It is a super-2 number, since 2×661320356² = 874689226519933472, which contains 22 as substring.

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, 125990 + ... + 131133.

It is an arithmetic number, because the mean of its divisors is an integer number (96592916).

Almost surely, 2^661320356 is an apocalyptic number.

It is an amenable number.

661320356 is a deficient number, since it is larger than the sum of its proper divisors (497794636).

661320356 is a wasteful number, since it uses less digits than its factorization.

661320356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257770 (or 257768 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 32.

The square root of 661320356 is about 25716.1497118056. The cubic root of 661320356 is about 871.2389781010.

The spelling of 661320356 in words is "six hundred sixty-one million, three hundred twenty thousand, three hundred fifty-six".