21402464 has 24 divisors (see below), whose sum is σ = 43590960. Its totient is φ = 10331776.

The previous prime is 21402419. The next prime is 21402467. The reversal of 21402464 is 46420412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21402467) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10604 + ... + 12459.

It is an arithmetic number, because the mean of its divisors is an integer number (1816290).

Almost surely, 2^21402464 is an apocalyptic number.

It is an amenable number.

21402464 is an abundant number, since it is smaller than the sum of its proper divisors (22188496).

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

21402464 is a wasteful number, since it uses less digits than its factorization.

21402464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23102 (or 23094 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 23.

The square root of 21402464 is about 4626.2797148465. The cubic root of 21402464 is about 277.6437650217.

Adding to 21402464 its reverse (46420412), we get a palindrome (67822876).

The spelling of 21402464 in words is "twenty-one million, four hundred two thousand, four hundred sixty-four".