661489056 has 36 divisors (see below), whose sum is σ = 1881110322. Its totient is φ = 220496256.

The previous prime is 661489051. The next prime is 661489079. The reversal of 661489056 is 650984166.

It can be written as a sum of positive squares in only one way, i.e., 661312656 + 176400 = 25716^2 + 420^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×661489056² = 875135542415542272, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (661489051) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1148131 + ... + 1148706.

Almost surely, 2^661489056 is an apocalyptic number.

It is an amenable number.

661489056 is an abundant number, since it is smaller than the sum of its proper divisors (1219621266).

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

661489056 is a wasteful number, since it uses less digits than its factorization.

661489056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2296853 (or 2296842 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The square root of 661489056 is about 25719.4295426629. The cubic root of 661489056 is about 871.3130549173.

The spelling of 661489056 in words is "six hundred sixty-one million, four hundred eighty-nine thousand, fifty-six".