1561365900 has 108 divisors (see below), whose sum is σ = 4912466832. Its totient is φ = 414794880.

The previous prime is 1561365889. The next prime is 1561365913. The reversal of 1561365900 is 95631651.

1561365900 is a `hidden beast` number, since 1 + 5 + 61 + 3 + 6 + 590 + 0 = 666.

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 35 ways as a sum of consecutive naturals, for example, 246169 + ... + 252431.

It is an arithmetic number, because the mean of its divisors is an integer number (45485804).

Almost surely, 2^1561365900 is an apocalyptic number.

1561365900 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1561365900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2456233416).

1561365900 is an abundant number, since it is smaller than the sum of its proper divisors (3351100932).

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

1561365900 is a wasteful number, since it uses less digits than its factorization.

1561365900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6560 (or 6550 counting only the distinct ones).

The product of its (nonzero) digits is 24300, while the sum is 36.

The square root of 1561365900 is about 39514.1227917311. The cubic root of 1561365900 is about 1160.1163924034.

The spelling of 1561365900 in words is "one billion, five hundred sixty-one million, three hundred sixty-five thousand, nine hundred".