21406059 has 32 divisors (see below), whose sum is σ = 33122880. Its totient is φ = 13651200.

The previous prime is 21406037. The next prime is 21406069. The reversal of 21406059 is 95060412.

It is not a de Polignac number, because 21406059 - 2⁷ = 21405931 is a prime.

It is a super-2 number, since 2×21406059² = 916438723822962, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21406069) 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, 67369 + ... + 67685.

It is an arithmetic number, because the mean of its divisors is an integer number (1035090).

Almost surely, 2^21406059 is an apocalyptic number.

21406059 is a deficient number, since it is larger than the sum of its proper divisors (11716821).

21406059 is a wasteful number, since it uses less digits than its factorization.

21406059 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 428 (or 422 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 21406059 is about 4626.6682396731. The cubic root of 21406059 is about 277.6593095474.

The spelling of 21406059 in words is "twenty-one million, four hundred six thousand, fifty-nine".