21402924 has 12 divisors (see below), whose sum is σ = 49940184. Its totient is φ = 7134304.

The previous prime is 21402919. The next prime is 21402947. The reversal of 21402924 is 42920412.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 21402894 and 21402903.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 891777 + ... + 891800.

It is an arithmetic number, because the mean of its divisors is an integer number (4161682).

Almost surely, 2^21402924 is an apocalyptic number.

It is an amenable number.

21402924 is an abundant number, since it is smaller than the sum of its proper divisors (28537260).

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

21402924 is a wasteful number, since it uses less digits than its factorization.

21402924 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1783584 (or 1783582 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 21402924 is about 4626.3294305529. The cubic root of 21402924 is about 277.6457541262.

The spelling of 21402924 in words is "twenty-one million, four hundred two thousand, nine hundred twenty-four".