661644922 has 4 divisors (see below), whose sum is σ = 992467386. Its totient is φ = 330822460.

The previous prime is 661644877. The next prime is 661644937. The reversal of 661644922 is 229446166.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 528034441 + 133610481 = 22979^2 + 11559^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165411229 + ... + 165411232.

Almost surely, 2^661644922 is an apocalyptic number.

661644922 is a deficient number, since it is larger than the sum of its proper divisors (330822464).

661644922 is a wasteful number, since it uses less digits than its factorization.

661644922 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330822463.

The product of its digits is 124416, while the sum is 40.

The square root of 661644922 is about 25722.4594858268. The cubic root of 661644922 is about 871.3814850820.

The spelling of 661644922 in words is "six hundred sixty-one million, six hundred forty-four thousand, nine hundred twenty-two".