18690640 has 40 divisors (see below), whose sum is σ = 43747200. Its totient is φ = 7426176.

The previous prime is 18690611. The next prime is 18690641. The reversal of 18690640 is 4609681.

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 18690596 and 18690605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18690641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12661 + ... + 14059.

It is an arithmetic number, because the mean of its divisors is an integer number (1093680).

Almost surely, 2^18690640 is an apocalyptic number.

18690640 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 18690640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21873600).

18690640 is an abundant number, since it is smaller than the sum of its proper divisors (25056560).

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

18690640 is a wasteful number, since it uses less digits than its factorization.

18690640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1579 (or 1573 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 18690640 is about 4323.2672829701. The cubic root of 18690640 is about 265.3839929757.

The spelling of 18690640 in words is "eighteen million, six hundred ninety thousand, six hundred forty".