21158365 has 8 divisors (see below), whose sum is σ = 25980768. Its totient is φ = 16532880.

The previous prime is 21158329. The next prime is 21158377. The reversal of 21158365 is 56385112.

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

It is not a de Polignac number, because 21158365 - 2¹⁹ = 20634077 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48991 + ... + 49420.

It is an arithmetic number, because the mean of its divisors is an integer number (3247596).

Almost surely, 2^21158365 is an apocalyptic number.

It is an amenable number.

21158365 is a deficient number, since it is larger than the sum of its proper divisors (4822403).

21158365 is an equidigital number, since it uses as much as digits as its factorization.

21158365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98459.

The product of its digits is 7200, while the sum is 31.

The square root of 21158365 is about 4599.8222791756. The cubic root of 21158365 is about 276.5842006762.

The spelling of 21158365 in words is "twenty-one million, one hundred fifty-eight thousand, three hundred sixty-five".