1251120816 has 400 divisors, whose sum is σ = 4321152000. Its totient is φ = 345254400.

The previous prime is 1251120769. The next prime is 1251120833. The reversal of 1251120816 is 6180211521.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 1251120816.

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 79 ways as a sum of consecutive naturals, for example, 8396710 + ... + 8396858.

It is an arithmetic number, because the mean of its divisors is an integer number (10802880).

Almost surely, 2^1251120816 is an apocalyptic number.

1251120816 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 1251120816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2160576000).

1251120816 is an abundant number, since it is smaller than the sum of its proper divisors (3070031184).

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

1251120816 is a wasteful number, since it uses less digits than its factorization.

1251120816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230 (or 215 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 27.

The square root of 1251120816 is about 35371.1862396499. The cubic root of 1251120816 is about 1077.5392121503.

The spelling of 1251120816 in words is "one billion, two hundred fifty-one million, one hundred twenty thousand, eight hundred sixteen".