21598249 has 2 divisors, whose sum is σ = 21598250. Its totient is φ = 21598248.

The previous prime is 21598207. The next prime is 21598259. The reversal of 21598249 is 94289512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18429849 + 3168400 = 4293^2 + 1780^2 .

It is a cyclic number.

It is not a de Polignac number, because 21598249 - 2²³ = 13209641 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21598259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10799124 + 10799125.

It is an arithmetic number, because the mean of its divisors is an integer number (10799125).

Almost surely, 2^21598249 is an apocalyptic number.

It is an amenable number.

21598249 is a deficient number, since it is larger than the sum of its proper divisors (1).

21598249 is an equidigital number, since it uses as much as digits as its factorization.

21598249 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51840, while the sum is 40.

The square root of 21598249 is about 4647.3916340244. The cubic root of 21598249 is about 278.4878044226.

The spelling of 21598249 in words is "twenty-one million, five hundred ninety-eight thousand, two hundred forty-nine".