18136640 has 84 divisors (see below), whose sum is σ = 45870876. Its totient is φ = 6829056.

The previous prime is 18136633. The next prime is 18136667. The reversal of 18136640 is 4663181.

It can be written as a sum of positive squares in 2 ways, for example, as 5914624 + 12222016 = 2432^2 + 3496^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 115442 + ... + 115598.

Almost surely, 2^18136640 is an apocalyptic number.

18136640 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 18136640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22935438).

18136640 is an abundant number, since it is smaller than the sum of its proper divisors (27734236).

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

18136640 is a wasteful number, since it uses less digits than its factorization.

18136640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212 (or 183 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 18136640 is about 4258.7134207411. The cubic root of 18136640 is about 262.7356130976.

The spelling of 18136640 in words is "eighteen million, one hundred thirty-six thousand, six hundred forty".