21424878 has 32 divisors (see below), whose sum is σ = 48777120. Its totient is φ = 6966720.

The previous prime is 21424877. The next prime is 21424943. The reversal of 21424878 is 87842412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21424877) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2625 + ... + 7052.

It is an arithmetic number, because the mean of its divisors is an integer number (1524285).

Almost surely, 2^21424878 is an apocalyptic number.

21424878 is an abundant number, since it is smaller than the sum of its proper divisors (27352242).

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

21424878 is a wasteful number, since it uses less digits than its factorization.

21424878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9729 (or 9723 counting only the distinct ones).

The product of its digits is 28672, while the sum is 36.

The square root of 21424878 is about 4628.7015457901. The cubic root of 21424878 is about 277.7406531838.

The spelling of 21424878 in words is "twenty-one million, four hundred twenty-four thousand, eight hundred seventy-eight".