21457533 has 8 divisors (see below), whose sum is σ = 29095200. Its totient is φ = 14062448.

The previous prime is 21457523. The next prime is 21457603. The reversal of 21457533 is 33575412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21457533 - 2⁹ = 21457021 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21457533.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21457523) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60438 + ... + 60791.

It is an arithmetic number, because the mean of its divisors is an integer number (3636900).

Almost surely, 2^21457533 is an apocalyptic number.

It is an amenable number.

21457533 is a deficient number, since it is larger than the sum of its proper divisors (7637667).

21457533 is a wasteful number, since it uses less digits than its factorization.

21457533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121291.

The product of its digits is 12600, while the sum is 30.

The square root of 21457533 is about 4632.2276498462. The cubic root of 21457533 is about 277.8816888693.

The spelling of 21457533 in words is "twenty-one million, four hundred fifty-seven thousand, five hundred thirty-three".