21402472 has 32 divisors (see below), whose sum is σ = 49392000. Its totient is φ = 8466624.

The previous prime is 21402467. The next prime is 21402481. The reversal of 21402472 is 27420412.

It is a happy number.

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 7 ways as a sum of consecutive naturals, for example, 13972 + ... + 15427.

It is an arithmetic number, because the mean of its divisors is an integer number (1543500).

Almost surely, 2^21402472 is an apocalyptic number.

It is an amenable number.

21402472 is an abundant number, since it is smaller than the sum of its proper divisors (27989528).

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

21402472 is a wasteful number, since it uses less digits than its factorization.

21402472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29425 (or 29421 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 22.

The square root of 21402472 is about 4626.2805794720. The cubic root of 21402472 is about 277.6437996150.

Adding to 21402472 its reverse (27420412), we get a palindrome (48822884).

The spelling of 21402472 in words is "twenty-one million, four hundred two thousand, four hundred seventy-two".