21109151 has 6 divisors (see below), whose sum is σ = 24555600. Its totient is φ = 18093516.

The previous prime is 21109139. The next prime is 21109159. The reversal of 21109151 is 15190112.

It is not a de Polignac number, because 21109151 - 2¹⁸ = 20847007 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 (21109159) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 215351 + ... + 215448.

It is an arithmetic number, because the mean of its divisors is an integer number (4092600).

Almost surely, 2^21109151 is an apocalyptic number.

21109151 is a deficient number, since it is larger than the sum of its proper divisors (3446449).

21109151 is an equidigital number, since it uses as much as digits as its factorization.

21109151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 430813 (or 430806 counting only the distinct ones).

The product of its (nonzero) digits is 90, while the sum is 20.

The square root of 21109151 is about 4594.4696103032. The cubic root of 21109151 is about 276.3695908024.

Adding to 21109151 its reverse (15190112), we get a palindrome (36299263).

The spelling of 21109151 in words is "twenty-one million, one hundred nine thousand, one hundred fifty-one".