1561551372 has 30 divisors (see below), whose sum is σ = 4082204588. Its totient is φ = 520517016.

The previous prime is 1561551361. The next prime is 1561551389. The reversal of 1561551372 is 2731551651.

It is a happy number.

1561551372 is a `hidden beast` number, since 1 + 5 + 615 + 5 + 1 + 37 + 2 = 666.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 2409478 + ... + 2410125.

Almost surely, 2^1561551372 is an apocalyptic number.

1561551372 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1561551372 is an abundant number, since it is smaller than the sum of its proper divisors (2520653216).

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

1561551372 is a wasteful number, since it uses less digits than its factorization.

1561551372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4819619 (or 4819608 counting only the distinct ones).

The product of its digits is 31500, while the sum is 36.

The square root of 1561551372 is about 39516.4696297632. The cubic root of 1561551372 is about 1160.1623266691.

The spelling of 1561551372 in words is "one billion, five hundred sixty-one million, five hundred fifty-one thousand, three hundred seventy-two".