21498539 has 2 divisors, whose sum is σ = 21498540. Its totient is φ = 21498538.

The previous prime is 21498511. The next prime is 21498551. The reversal of 21498539 is 93589412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21498539 - 2²⁴ = 4721323 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21498496 and 21498505.

It is not a weakly prime, because it can be changed into another prime (21498439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10749269 + 10749270.

It is an arithmetic number, because the mean of its divisors is an integer number (10749270).

Almost surely, 2^21498539 is an apocalyptic number.

21498539 is a deficient number, since it is larger than the sum of its proper divisors (1).

21498539 is an equidigital number, since it uses as much as digits as its factorization.

21498539 is an evil number, because the sum of its binary digits is even.

The product of its digits is 77760, while the sum is 41.

The square root of 21498539 is about 4636.6517013897. The cubic root of 21498539 is about 278.0585896903.

The spelling of 21498539 in words is "twenty-one million, four hundred ninety-eight thousand, five hundred thirty-nine".