1561977964 has 12 divisors (see below), whose sum is σ = 2734347784. Its totient is φ = 780735744.

The previous prime is 1561977947. The next prime is 1561978009. The reversal of 1561977964 is 4697791651.

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, 49077 + ... + 74380.

Almost surely, 2^1561977964 is an apocalyptic number.

It is an amenable number.

1561977964 is a deficient number, since it is larger than the sum of its proper divisors (1172369820).

1561977964 is a wasteful number, since it uses less digits than its factorization.

1561977964 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126624 (or 126622 counting only the distinct ones).

The product of its digits is 2857680, while the sum is 55.

The square root of 1561977964 is about 39521.8669093453. The cubic root of 1561977964 is about 1160.2679632634.

The spelling of 1561977964 in words is "one billion, five hundred sixty-one million, nine hundred seventy-seven thousand, nine hundred sixty-four".