21457332 has 192 divisors, whose sum is σ = 67737600. Its totient is φ = 5806080.

The previous prime is 21457313. The next prime is 21457339. The reversal of 21457332 is 23375412.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 21457296 and 21457305.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21457339) 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 63 ways as a sum of consecutive naturals, for example, 692157 + ... + 692187.

It is an arithmetic number, because the mean of its divisors is an integer number (352800).

Almost surely, 2^21457332 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21457332, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33868800).

21457332 is an abundant number, since it is smaller than the sum of its proper divisors (46280268).

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

21457332 is a wasteful number, since it uses less digits than its factorization.

21457332 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103 (or 95 counting only the distinct ones).

The product of its digits is 5040, while the sum is 27.

The square root of 21457332 is about 4632.2059539705. The cubic root of 21457332 is about 277.8808211959.

The spelling of 21457332 in words is "twenty-one million, four hundred fifty-seven thousand, three hundred thirty-two".