1561861983 has 16 divisors (see below), whose sum is σ = 2310307200. Its totient is φ = 930538080.

The previous prime is 1561861969. The next prime is 1561861993. The reversal of 1561861983 is 3891681651.

It is not a de Polignac number, because 1561861983 - 2⁴ = 1561861967 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561861993) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 399148 + ... + 403041.

It is an arithmetic number, because the mean of its divisors is an integer number (144394200).

Almost surely, 2^1561861983 is an apocalyptic number.

1561861983 is a deficient number, since it is larger than the sum of its proper divisors (748445217).

1561861983 is a wasteful number, since it uses less digits than its factorization.

1561861983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 802262.

The product of its digits is 311040, while the sum is 48.

The square root of 1561861983 is about 39520.3995804698. The cubic root of 1561861983 is about 1160.2392448964.

The spelling of 1561861983 in words is "one billion, five hundred sixty-one million, eight hundred sixty-one thousand, nine hundred eighty-three".