18290640 has 80 divisors (see below), whose sum is σ = 60049728. Its totient is φ = 4589568.

The previous prime is 18290639. The next prime is 18290647. The reversal of 18290640 is 4609281.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 18290598 and 18290607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18290647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1839 + ... + 6321.

Almost surely, 2^18290640 is an apocalyptic number.

18290640 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 18290640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30024864).

18290640 is an abundant number, since it is smaller than the sum of its proper divisors (41759088).

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

18290640 is a wasteful number, since it uses less digits than its factorization.

18290640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4516 (or 4510 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 18290640 is about 4276.7557797938. The cubic root of 18290640 is about 263.4771562086.

The spelling of 18290640 in words is "eighteen million, two hundred ninety thousand, six hundred forty".