21102438 has 24 divisors (see below), whose sum is σ = 49096152. Its totient is φ = 6029184.

The previous prime is 21102421. The next prime is 21102439. The reversal of 21102438 is 83420112.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102439) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35595 + ... + 36182.

It is an arithmetic number, because the mean of its divisors is an integer number (2045673).

Almost surely, 2^21102438 is an apocalyptic number.

21102438 is an abundant number, since it is smaller than the sum of its proper divisors (27993714).

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

21102438 is a wasteful number, since it uses less digits than its factorization.

21102438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71796 (or 71789 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21102438 is about 4593.7389999868. The cubic root of 21102438 is about 276.3402912542.

The spelling of 21102438 in words is "twenty-one million, one hundred two thousand, four hundred thirty-eight".