21498813 has 48 divisors (see below), whose sum is σ = 38128896. Its totient is φ = 11404800.

The previous prime is 21498797. The next prime is 21498817. The reversal of 21498813 is 31889412.

It is not a de Polignac number, because 21498813 - 2⁴ = 21498797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21498817) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 53413 + ... + 53813.

It is an arithmetic number, because the mean of its divisors is an integer number (794352).

Almost surely, 2^21498813 is an apocalyptic number.

21498813 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21498813 is a deficient number, since it is larger than the sum of its proper divisors (16630083).

21498813 is a wasteful number, since it uses less digits than its factorization.

21498813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 474 (or 471 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 21498813 is about 4636.6812484793. The cubic root of 21498813 is about 278.0597709757.

The spelling of 21498813 in words is "twenty-one million, four hundred ninety-eight thousand, eight hundred thirteen".