21873373 has 4 divisors (see below), whose sum is σ = 23160060. Its totient is φ = 20586688.

The previous prime is 21873361. The next prime is 21873409. The reversal of 21873373 is 37337812.

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 15507844 + 6365529 = 3938^2 + 2523^2 .

It is a cyclic number.

It is not a de Polignac number, because 21873373 - 2⁹ = 21872861 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 (21873343) 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, 643318 + ... + 643351.

It is an arithmetic number, because the mean of its divisors is an integer number (5790015).

Almost surely, 2^21873373 is an apocalyptic number.

It is an amenable number.

21873373 is a deficient number, since it is larger than the sum of its proper divisors (1286687).

21873373 is a wasteful number, since it uses less digits than its factorization.

21873373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1286686.

The product of its digits is 21168, while the sum is 34.

The square root of 21873373 is about 4676.8977966169. The cubic root of 21873373 is about 279.6653016078.

The spelling of 21873373 in words is "twenty-one million, eight hundred seventy-three thousand, three hundred seventy-three".