21404684 has 24 divisors (see below), whose sum is σ = 43024128. Its totient is φ = 9127440.

The previous prime is 21404681. The next prime is 21404689. The reversal of 21404684 is 48640412.

It is a Smith number, since the sum of its digits (29) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21404681) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4097 + ... + 7719.

It is an arithmetic number, because the mean of its divisors is an integer number (1792672).

Almost surely, 2^21404684 is an apocalyptic number.

It is an amenable number.

21404684 is an abundant number, since it is smaller than the sum of its proper divisors (21619444).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21404684 is a wasteful number, since it uses less digits than its factorization.

21404684 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3845 (or 3843 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 29.

The square root of 21404684 is about 4626.5196422365. The cubic root of 21404684 is about 277.6533643502.

The spelling of 21404684 in words is "twenty-one million, four hundred four thousand, six hundred eighty-four".