1561568400 has 180 divisors, whose sum is σ = 6193329792. Its totient is φ = 356924160.

The previous prime is 1561568383. The next prime is 1561568453. The reversal of 1561568400 is 48651651.

1561568400 is a `hidden beast` number, since 1 + 56 + 1 + 568 + 40 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (180).

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

It is a congruent number.

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, 5784 + ... + 56183.

Almost surely, 2^1561568400 is an apocalyptic number.

1561568400 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 1561568400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3096664896).

1561568400 is an abundant number, since it is smaller than the sum of its proper divisors (4631761392).

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

1561568400 is a wasteful number, since it uses less digits than its factorization.

1561568400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61998 (or 61984 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The square root of 1561568400 is about 39516.6850836454. The cubic root of 1561568400 is about 1160.1665436661.

The spelling of 1561568400 in words is "one billion, five hundred sixty-one million, five hundred sixty-eight thousand, four hundred".