21498673 has 4 divisors (see below), whose sum is σ = 24569920. Its totient is φ = 18427428.

The previous prime is 21498649. The next prime is 21498679. The reversal of 21498673 is 37689412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21498673 - 2⁵ = 21498641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21498679) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1535613 + ... + 1535626.

It is an arithmetic number, because the mean of its divisors is an integer number (6142480).

Almost surely, 2^21498673 is an apocalyptic number.

It is an amenable number.

21498673 is a deficient number, since it is larger than the sum of its proper divisors (3071247).

21498673 is an equidigital number, since it uses as much as digits as its factorization.

21498673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3071246.

The product of its digits is 72576, while the sum is 40.

The square root of 21498673 is about 4636.6661514498. Note that the first 3 decimals coincide. The cubic root of 21498673 is about 278.0591674005.

The spelling of 21498673 in words is "twenty-one million, four hundred ninety-eight thousand, six hundred seventy-three".