21098231 has 24 divisors (see below), whose sum is σ = 27126912. Its totient is φ = 15940800.

The previous prime is 21098221. The next prime is 21098257. The reversal of 21098231 is 13289012.

It is not a de Polignac number, because 21098231 - 2¹⁰ = 21097207 is a prime.

It is a super-2 number, since 2×21098231² = 890270702658722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21098231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21098201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 129356 + ... + 129518.

It is an arithmetic number, because the mean of its divisors is an integer number (1130288).

Almost surely, 2^21098231 is an apocalyptic number.

21098231 is a deficient number, since it is larger than the sum of its proper divisors (6028681).

21098231 is a wasteful number, since it uses less digits than its factorization.

21098231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 263 (or 222 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 21098231 is about 4593.2810713040. The cubic root of 21098231 is about 276.3219262218.

The spelling of 21098231 in words is "twenty-one million, ninety-eight thousand, two hundred thirty-one".