1561577256 has 96 divisors (see below), whose sum is σ = 4332182400. Its totient is φ = 507928320.

The previous prime is 1561577233. The next prime is 1561577257. The reversal of 1561577256 is 6527751651.

1561577256 is a `hidden beast` number, since 1 + 5 + 615 + 7 + 7 + 25 + 6 = 666.

It is not an unprimeable number, because it can be changed into a prime (1561577257) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1925091 + ... + 1925901.

It is an arithmetic number, because the mean of its divisors is an integer number (45126900).

Almost surely, 2^1561577256 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1561577256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2166091200).

1561577256 is an abundant number, since it is smaller than the sum of its proper divisors (2770605144).

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

1561577256 is a wasteful number, since it uses less digits than its factorization.

1561577256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1439 (or 1432 counting only the distinct ones).

The product of its digits is 441000, while the sum is 45.

The square root of 1561577256 is about 39516.7971374199. The cubic root of 1561577256 is about 1160.1687368490.

The spelling of 1561577256 in words is "one billion, five hundred sixty-one million, five hundred seventy-seven thousand, two hundred fifty-six".