21890518 has 16 divisors (see below), whose sum is σ = 35526960. Its totient is φ = 10056096.

The previous prime is 21890513. The next prime is 21890573. The reversal of 21890518 is 81509812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21890513) 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, 4048 + ... + 7756.

It is an arithmetic number, because the mean of its divisors is an integer number (2220435).

Almost surely, 2^21890518 is an apocalyptic number.

21890518 is a deficient number, since it is larger than the sum of its proper divisors (13636442).

21890518 is a wasteful number, since it uses less digits than its factorization.

21890518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3951.

The product of its (nonzero) digits is 5760, while the sum is 34.

The square root of 21890518 is about 4678.7303833412. The cubic root of 21890518 is about 279.7383525171.

The spelling of 21890518 in words is "twenty-one million, eight hundred ninety thousand, five hundred eighteen".