21798959 has 16 divisors (see below), whose sum is σ = 26940480. Its totient is φ = 17176320.

The previous prime is 21798911. The next prime is 21798961. The reversal of 21798959 is 95989712.

It is a happy number.

It is not a de Polignac number, because 21798959 - 2⁸ = 21798703 is a prime.

It is a super-2 number, since 2×21798959² = 950389226967362, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21798559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38027 + ... + 38595.

It is an arithmetic number, because the mean of its divisors is an integer number (1683780).

Almost surely, 2^21798959 is an apocalyptic number.

21798959 is a deficient number, since it is larger than the sum of its proper divisors (5141521).

21798959 is a wasteful number, since it uses less digits than its factorization.

21798959 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1010.

The product of its digits is 408240, while the sum is 50.

The square root of 21798959 is about 4668.9355317888. The cubic root of 21798959 is about 279.3477974839.

The spelling of 21798959 in words is "twenty-one million, seven hundred ninety-eight thousand, nine hundred fifty-nine".