21239733 has 8 divisors (see below), whose sum is σ = 28595008. Its totient is φ = 14022144.

The previous prime is 21239731. The next prime is 21239753. The reversal of 21239733 is 33793212.

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

It is not a de Polignac number, because 21239733 - 2¹ = 21239731 is a prime.

It is a super-2 number, since 2×21239733² = 902252515822578, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21239733.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21239731) 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, 34060 + ... + 34677.

It is an arithmetic number, because the mean of its divisors is an integer number (3574376).

Almost surely, 2^21239733 is an apocalyptic number.

It is an amenable number.

21239733 is a deficient number, since it is larger than the sum of its proper divisors (7355275).

21239733 is a wasteful number, since it uses less digits than its factorization.

21239733 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68843.

The product of its digits is 6804, while the sum is 30.

The square root of 21239733 is about 4608.6584815974. The cubic root of 21239733 is about 276.9382972819.

The spelling of 21239733 in words is "twenty-one million, two hundred thirty-nine thousand, seven hundred thirty-three".