21165373 has 8 divisors (see below), whose sum is σ = 22356800. Its totient is φ = 19981728.

The previous prime is 21165299. The next prime is 21165379. The reversal of 21165373 is 37356112.

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

It is a cyclic number.

It is not a de Polignac number, because 21165373 - 2¹⁷ = 21034301 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 (21165379) 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, 4168 + ... + 7726.

It is an arithmetic number, because the mean of its divisors is an integer number (2794600).

Almost surely, 2^21165373 is an apocalyptic number.

It is an amenable number.

21165373 is a deficient number, since it is larger than the sum of its proper divisors (1191427).

21165373 is a wasteful number, since it uses less digits than its factorization.

21165373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3891.

The product of its digits is 3780, while the sum is 28.

The square root of 21165373 is about 4600.5839846698. The cubic root of 21165373 is about 276.6147337242.

The spelling of 21165373 in words is "twenty-one million, one hundred sixty-five thousand, three hundred seventy-three".