21372833 has 4 divisors (see below), whose sum is σ = 21776148. Its totient is φ = 20969520.

The previous prime is 21372811. The next prime is 21372839. The reversal of 21372833 is 33827312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19651489 + 1721344 = 4433^2 + 1312^2 .

It is a cyclic number.

It is not a de Polignac number, because 21372833 - 2⁸ = 21372577 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21372796 and 21372805.

It is not an unprimeable number, because it can be changed into a prime (21372839) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 201578 + ... + 201683.

It is an arithmetic number, because the mean of its divisors is an integer number (5444037).

Almost surely, 2^21372833 is an apocalyptic number.

It is an amenable number.

21372833 is a deficient number, since it is larger than the sum of its proper divisors (403315).

21372833 is an equidigital number, since it uses as much as digits as its factorization.

21372833 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 403314.

The product of its digits is 6048, while the sum is 29.

The square root of 21372833 is about 4623.0761404069. The cubic root of 21372833 is about 277.5155763245.

The spelling of 21372833 in words is "twenty-one million, three hundred seventy-two thousand, eight hundred thirty-three".