21428252 has 6 divisors (see below), whose sum is σ = 37499448. Its totient is φ = 10714124.

The previous prime is 21428243. The next prime is 21428317. The reversal of 21428252 is 25282412.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2678528 + ... + 2678535.

It is an arithmetic number, because the mean of its divisors is an integer number (6249908).

Almost surely, 2^21428252 is an apocalyptic number.

It is an amenable number.

21428252 is a deficient number, since it is larger than the sum of its proper divisors (16071196).

21428252 is a wasteful number, since it uses less digits than its factorization.

21428252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5357067 (or 5357065 counting only the distinct ones).

The product of its digits is 2560, while the sum is 26.

The square root of 21428252 is about 4629.0659965051. The cubic root of 21428252 is about 277.7552319953.

The spelling of 21428252 in words is "twenty-one million, four hundred twenty-eight thousand, two hundred fifty-two".