1809401256 has 144 divisors (see below), whose sum is σ = 5606955900. Its totient is φ = 523911168.

The previous prime is 1809401221. The next prime is 1809401327. The reversal of 1809401256 is 6521049081.

It can be written as a sum of positive squares in 6 ways, for example, as 1390544100 + 418857156 = 37290^2 + 20466^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 1809401256.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 267160 + ... + 273848.

Almost surely, 2^1809401256 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 1809401256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2803477950).

1809401256 is an abundant number, since it is smaller than the sum of its proper divisors (3797554644).

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

1809401256 is a wasteful number, since it uses less digits than its factorization.

1809401256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6748 (or 6724 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 1809401256 is about 42537.0574440687. The cubic root of 1809401256 is about 1218.5545130559.

The spelling of 1809401256 in words is "one billion, eight hundred nine million, four hundred one thousand, two hundred fifty-six".