18091944 has 128 divisors (see below), whose sum is σ = 57456000. Its totient is φ = 5225472.

The previous prime is 18091939. The next prime is 18091963. The reversal of 18091944 is 44919081.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

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

It is a junction number, because it is equal to n+sod(n) for n = 18091899 and 18091908.

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, 47547 + ... + 47925.

It is an arithmetic number, because the mean of its divisors is an integer number (448875).

Almost surely, 2^18091944 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 18091944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28728000).

18091944 is an abundant number, since it is smaller than the sum of its proper divisors (39364056).

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

18091944 is a wasteful number, since it uses less digits than its factorization.

18091944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 424 (or 414 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 18091944 is about 4253.4625894676. The cubic root of 18091944 is about 262.5196066988.

The spelling of 18091944 in words is "eighteen million, ninety-one thousand, nine hundred forty-four".