18256805640 has 96 divisors (see below), whose sum is σ = 59394605400. Its totient is φ = 4863559680.

The previous prime is 18256805629. The next prime is 18256805659. The reversal of 18256805640 is 4650865281.

18256805640 is a `hidden beast` number, since 1 + 8 + 2 + 5 + 6 + 80 + 564 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 10144921284 + 8111884356 = 100722^2 + 90066^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 338110 + ... + 388370.

Almost surely, 2^18256805640 is an apocalyptic number.

18256805640 is a gapful number since it is divisible by the number (10) 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 18256805640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29697302700).

18256805640 is an abundant number, since it is smaller than the sum of its proper divisors (41137799760).

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

18256805640 is a wasteful number, since it uses less digits than its factorization.

18256805640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51287 (or 51280 counting only the distinct ones).

The product of its (nonzero) digits is 460800, while the sum is 45.

The spelling of 18256805640 in words is "eighteen billion, two hundred fifty-six million, eight hundred five thousand, six hundred forty".