1231561056 has 192 divisors, whose sum is σ = 3856398336. Its totient is φ = 339763200.

The previous prime is 1231561049. The next prime is 1231561109. The reversal of 1231561056 is 6501651321.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 555406 + ... + 557618.

It is an arithmetic number, because the mean of its divisors is an integer number (20085408).

Almost surely, 2^1231561056 is an apocalyptic number.

1231561056 is a gapful number since it is divisible by the number (16) 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 1231561056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1928199168).

1231561056 is an abundant number, since it is smaller than the sum of its proper divisors (2624837280).

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

1231561056 is a wasteful number, since it uses less digits than its factorization.

1231561056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2285 (or 2277 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 30.

The square root of 1231561056 is about 35093.6042036152. The cubic root of 1231561056 is about 1071.8943517329.

The spelling of 1231561056 in words is "one billion, two hundred thirty-one million, five hundred sixty-one thousand, fifty-six".