21928373 has 4 divisors (see below), whose sum is σ = 21937740. Its totient is φ = 21919008.

The previous prime is 21928343. The next prime is 21928381. The reversal of 21928373 is 37382912.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 2365444 + 19562929 = 1538^2 + 4423^2 .

It is a cyclic number.

It is not a de Polignac number, because 21928373 - 2¹² = 21924277 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21928303) 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, 2273 + ... + 7001.

It is an arithmetic number, because the mean of its divisors is an integer number (5484435).

Almost surely, 2^21928373 is an apocalyptic number.

It is an amenable number.

21928373 is a deficient number, since it is larger than the sum of its proper divisors (9367).

21928373 is an equidigital number, since it uses as much as digits as its factorization.

21928373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9366.

The product of its digits is 18144, while the sum is 35.

The square root of 21928373 is about 4682.7740709968. The cubic root of 21928373 is about 279.8995090065.

The spelling of 21928373 in words is "twenty-one million, nine hundred twenty-eight thousand, three hundred seventy-three".