21351885 has 16 divisors (see below), whose sum is σ = 34236096. Its totient is φ = 11363328.

The previous prime is 21351829. The next prime is 21351893. The reversal of 21351885 is 58815312.

It is a happy number.

It is not a de Polignac number, because 21351885 - 2¹¹ = 21349837 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7422 + ... + 9888.

It is an arithmetic number, because the mean of its divisors is an integer number (2139756).

Almost surely, 2^21351885 is an apocalyptic number.

It is an amenable number.

21351885 is a deficient number, since it is larger than the sum of its proper divisors (12884211).

21351885 is a wasteful number, since it uses less digits than its factorization.

21351885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3052.

The product of its digits is 9600, while the sum is 33.

The square root of 21351885 is about 4620.8099939296. The cubic root of 21351885 is about 277.4248802430.

The spelling of 21351885 in words is "twenty-one million, three hundred fifty-one thousand, eight hundred eighty-five".