1561251156 has 24 divisors (see below), whose sum is σ = 3704665440. Its totient is φ = 511596192.

The previous prime is 1561251143. The next prime is 1561251161. The reversal of 1561251156 is 6511521651.

It is a super-2 number, since 2×1561251156² = 4875010344222672672, which contains 22 as substring.

It is a congruent number.

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, 1101871 + ... + 1103286.

It is an arithmetic number, because the mean of its divisors is an integer number (154361060).

Almost surely, 2^1561251156 is an apocalyptic number.

It is an amenable number.

1561251156 is an abundant number, since it is smaller than the sum of its proper divisors (2143414284).

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

1561251156 is a wasteful number, since it uses less digits than its factorization.

1561251156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2205223 (or 2205221 counting only the distinct ones).

The product of its digits is 9000, while the sum is 33.

The square root of 1561251156 is about 39512.6708284823. The cubic root of 1561251156 is about 1160.0879729159.

The spelling of 1561251156 in words is "one billion, five hundred sixty-one million, two hundred fifty-one thousand, one hundred fifty-six".