21118351 has 6 divisors (see below), whose sum is σ = 21872552. Its totient is φ = 20389320.

The previous prime is 21118343. The next prime is 21118373. The reversal of 21118351 is 15381112.

It is not a de Polignac number, because 21118351 - 2³ = 21118343 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 (21118381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11715 + ... + 13396.

Almost surely, 2^21118351 is an apocalyptic number.

21118351 is a deficient number, since it is larger than the sum of its proper divisors (754201).

21118351 is an equidigital number, since it uses as much as digits as its factorization.

21118351 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25169 (or 25140 counting only the distinct ones).

The product of its digits is 240, while the sum is 22.

The square root of 21118351 is about 4595.4707049442. The cubic root of 21118351 is about 276.4097350183.

Adding to 21118351 its reverse (15381112), we get a palindrome (36499463).

The spelling of 21118351 in words is "twenty-one million, one hundred eighteen thousand, three hundred fifty-one".