21408814 has 32 divisors (see below), whose sum is σ = 40559616. Its totient is φ = 8257920.

The previous prime is 21408787. The next prime is 21408823. The reversal of 21408814 is 41880412.

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, 3519 + ... + 7429.

It is an arithmetic number, because the mean of its divisors is an integer number (1267488).

Almost surely, 2^21408814 is an apocalyptic number.

21408814 is a deficient number, since it is larger than the sum of its proper divisors (19150802).

21408814 is a wasteful number, since it uses less digits than its factorization.

21408814 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3960.

The product of its (nonzero) digits is 2048, while the sum is 28.

The square root of 21408814 is about 4626.9659605404. The cubic root of 21408814 is about 277.6712207946.

It can be divided in two parts, 21408 and 814, that added together give a palindrome (22222).

The spelling of 21408814 in words is "twenty-one million, four hundred eight thousand, eight hundred fourteen".