1251275856 has 80 divisors (see below), whose sum is σ = 3417311040. Its totient is φ = 393431040.

The previous prime is 1251275797. The next prime is 1251275863. The reversal of 1251275856 is 6585721521.

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 15 ways as a sum of consecutive naturals, for example, 216946 + ... + 222638.

It is an arithmetic number, because the mean of its divisors is an integer number (42716388).

Almost surely, 2^1251275856 is an apocalyptic number.

1251275856 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 1251275856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1708655520).

1251275856 is an abundant number, since it is smaller than the sum of its proper divisors (2166035184).

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

1251275856 is a wasteful number, since it uses less digits than its factorization.

1251275856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5964 (or 5958 counting only the distinct ones).

The product of its digits is 168000, while the sum is 42.

The square root of 1251275856 is about 35373.3777861261. The cubic root of 1251275856 is about 1077.5837201831.

It can be divided in two parts, 1251 and 275856, that multiplied together give a triangular number (345095856 = T₂₆₂₇₁).

The spelling of 1251275856 in words is "one billion, two hundred fifty-one million, two hundred seventy-five thousand, eight hundred fifty-six".