21573793 has 4 divisors (see below), whose sum is σ = 22511808. Its totient is φ = 20635780.

The previous prime is 21573791. The next prime is 21573803. The reversal of 21573793 is 39737512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21573793 - 2¹ = 21573791 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21573791) 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, 468973 + ... + 469018.

It is an arithmetic number, because the mean of its divisors is an integer number (5627952).

Almost surely, 2^21573793 is an apocalyptic number.

21573793 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21573793 is a deficient number, since it is larger than the sum of its proper divisors (938015).

21573793 is an equidigital number, since it uses as much as digits as its factorization.

21573793 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 938014.

The product of its digits is 39690, while the sum is 37.

The square root of 21573793 is about 4644.7597354438. The cubic root of 21573793 is about 278.3826528433.

It can be divided in two parts, 21573 and 793, that added together give a triangular number (22366 = T₂₁₁).

The spelling of 21573793 in words is "twenty-one million, five hundred seventy-three thousand, seven hundred ninety-three".