21293428 has 48 divisors (see below), whose sum is σ = 41912640. Its totient is φ = 9402624.

The previous prime is 21293407. The next prime is 21293429. The reversal of 21293428 is 82439212.

Its product of digits (6912) is a multiple of the sum of its prime factors (256).

It is a self number, because there is not a number n which added to its sum of digits gives 21293428.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21293429) 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, 198951 + ... + 199057.

It is an arithmetic number, because the mean of its divisors is an integer number (873180).

Almost surely, 2^21293428 is an apocalyptic number.

It is an amenable number.

21293428 is a deficient number, since it is larger than the sum of its proper divisors (20619212).

21293428 is a wasteful number, since it uses less digits than its factorization.

21293428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256 (or 254 counting only the distinct ones).

The product of its digits is 6912, while the sum is 31.

The square root of 21293428 is about 4614.4802524228. The cubic root of 21293428 is about 277.1714717227.

The spelling of 21293428 in words is "twenty-one million, two hundred ninety-three thousand, four hundred twenty-eight".