21698859 has 32 divisors (see below), whose sum is σ = 36219904. Its totient is φ = 11249280.

The previous prime is 21698849. The next prime is 21698861. The reversal of 21698859 is 95889612.

It is a happy number.

It is not a de Polignac number, because 21698859 - 2⁵ = 21698827 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21698849) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16002 + ... + 17304.

It is an arithmetic number, because the mean of its divisors is an integer number (1131872).

Almost surely, 2^21698859 is an apocalyptic number.

21698859 is a deficient number, since it is larger than the sum of its proper divisors (14521045).

21698859 is a wasteful number, since it uses less digits than its factorization.

21698859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1387.

The product of its digits is 311040, while the sum is 48.

The square root of 21698859 is about 4658.2034090409. The cubic root of 21698859 is about 278.9195564641.

The spelling of 21698859 in words is "twenty-one million, six hundred ninety-eight thousand, eight hundred fifty-nine".