21190818 has 16 divisors (see below), whose sum is σ = 46234656. Its totient is φ = 6421440.

The previous prime is 21190817. The next prime is 21190837. The reversal of 21190818 is 81809112.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21190817) 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, 160471 + ... + 160602.

It is an arithmetic number, because the mean of its divisors is an integer number (2889666).

Almost surely, 2^21190818 is an apocalyptic number.

21190818 is an abundant number, since it is smaller than the sum of its proper divisors (25043838).

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

21190818 is a wasteful number, since it uses less digits than its factorization.

21190818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321089.

The product of its (nonzero) digits is 1152, while the sum is 30.

The square root of 21190818 is about 4603.3485638174. The cubic root of 21190818 is about 276.7255380276.

The spelling of 21190818 in words is "twenty-one million, one hundred ninety thousand, eight hundred eighteen".