1561917984 has 48 divisors (see below), whose sum is σ = 4472768160. Its totient is φ = 473308160.

The previous prime is 1561917977. The next prime is 1561918013. The reversal of 1561917984 is 4897191651.

It is a tau number, because it is divible by the number of its divisors (48).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 738489 + ... + 740600.

It is an arithmetic number, because the mean of its divisors is an integer number (93182670).

Almost surely, 2^1561917984 is an apocalyptic number.

It is an amenable number.

1561917984 is an abundant number, since it is smaller than the sum of its proper divisors (2910850176).

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

1561917984 is a wasteful number, since it uses less digits than its factorization.

1561917984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1479113 (or 1479105 counting only the distinct ones).

The product of its digits is 544320, while the sum is 51.

The square root of 1561917984 is about 39521.1080816315. The cubic root of 1561917984 is about 1160.2531116319.

The spelling of 1561917984 in words is "one billion, five hundred sixty-one million, nine hundred seventeen thousand, nine hundred eighty-four".