21102424 has 32 divisors (see below), whose sum is σ = 45561600. Its totient is φ = 8975520.

The previous prime is 21102421. The next prime is 21102439. The reversal of 21102424 is 42420112.

It is a junction number, because it is equal to n+sod(n) for n = 21102398 and 21102407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102421) 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, 6429 + ... + 9139.

It is an arithmetic number, because the mean of its divisors is an integer number (1423800).

Almost surely, 2^21102424 is an apocalyptic number.

It is an amenable number.

21102424 is an abundant number, since it is smaller than the sum of its proper divisors (24459176).

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

21102424 is a wasteful number, since it uses less digits than its factorization.

21102424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2863 (or 2859 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 21102424 is about 4593.7374761734. The cubic root of 21102424 is about 276.3402301433.

Adding to 21102424 its reverse (42420112), we get a palindrome (63522536).

The spelling of 21102424 in words is "twenty-one million, one hundred two thousand, four hundred twenty-four".