21958859 has 12 divisors (see below), whose sum is σ = 24767568. Its totient is φ = 19316880.

The previous prime is 21958847. The next prime is 21958877. The reversal of 21958859 is 95885912.

It is not a de Polignac number, because 21958859 - 2¹² = 21954763 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21958459) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 80894 + ... + 81164.

It is an arithmetic number, because the mean of its divisors is an integer number (2063964).

Almost surely, 2^21958859 is an apocalyptic number.

21958859 is a deficient number, since it is larger than the sum of its proper divisors (2808709).

21958859 is an equidigital number, since it uses as much as digits as its factorization.

21958859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 578 (or 307 counting only the distinct ones).

The product of its digits is 259200, while the sum is 47.

The square root of 21958859 is about 4686.0280622292. The cubic root of 21958859 is about 280.0291593782.

The spelling of 21958859 in words is "twenty-one million, nine hundred fifty-eight thousand, eight hundred fifty-nine".