21428874 has 80 divisors (see below), whose sum is σ = 52690176. Its totient is φ = 6480000.

The previous prime is 21428861. The next prime is 21428887. The reversal of 21428874 is 47882412.

It is an interprime number because it is at equal distance from previous prime (21428861) and next prime (21428887).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 85249 + ... + 85499.

Almost surely, 2^21428874 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21428874, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26345088).

21428874 is an abundant number, since it is smaller than the sum of its proper divisors (31261302).

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

21428874 is a wasteful number, since it uses less digits than its factorization.

21428874 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 313 (or 304 counting only the distinct ones).

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

The square root of 21428874 is about 4629.1331801969. The cubic root of 21428874 is about 277.7579194455.

The spelling of 21428874 in words is "twenty-one million, four hundred twenty-eight thousand, eight hundred seventy-four".