21428532 has 36 divisors (see below), whose sum is σ = 54701920. Its totient is φ = 7072272.

The previous prime is 21428531. The next prime is 21428549. The reversal of 21428532 is 23582412.

It is a tau number, because it is divible by the number of its divisors (36).

It is a junction number, because it is equal to n+sod(n) for n = 21428496 and 21428505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21428531) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 819 + ... + 6597.

Almost surely, 2^21428532 is an apocalyptic number.

It is an amenable number.

21428532 is an abundant number, since it is smaller than the sum of its proper divisors (33273388).

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

21428532 is a wasteful number, since it uses less digits than its factorization.

21428532 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5892 (or 5887 counting only the distinct ones).

The product of its digits is 3840, while the sum is 27.

The square root of 21428532 is about 4629.0962400883. The cubic root of 21428532 is about 277.7564417864.

The spelling of 21428532 in words is "twenty-one million, four hundred twenty-eight thousand, five hundred thirty-two".