21040818 has 16 divisors (see below), whose sum is σ = 42142656. Its totient is φ = 7003440.

The previous prime is 21040807. The next prime is 21040879. The reversal of 21040818 is 81804012.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2808 + ... + 7068.

It is an arithmetic number, because the mean of its divisors is an integer number (2633916).

Almost surely, 2^21040818 is an apocalyptic number.

21040818 is an abundant number, since it is smaller than the sum of its proper divisors (21101838).

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

21040818 is a wasteful number, since it uses less digits than its factorization.

21040818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5089.

The product of its (nonzero) digits is 512, while the sum is 24.

The square root of 21040818 is about 4587.0271418425. The cubic root of 21040818 is about 276.0710539599.

The spelling of 21040818 in words is "twenty-one million, forty thousand, eight hundred eighteen".