21611051 has 32 divisors (see below), whose sum is σ = 28200960. Its totient is φ = 16077600.

The previous prime is 21611041. The next prime is 21611087. The reversal of 21611051 is 15011612.

It is not a de Polignac number, because 21611051 - 2¹⁰ = 21610027 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21611011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 304346 + ... + 304416.

It is an arithmetic number, because the mean of its divisors is an integer number (881280).

Almost surely, 2^21611051 is an apocalyptic number.

21611051 is a deficient number, since it is larger than the sum of its proper divisors (6589909).

21611051 is a wasteful number, since it uses less digits than its factorization.

21611051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215.

The product of its (nonzero) digits is 60, while the sum is 17.

The square root of 21611051 is about 4648.7687617261. The cubic root of 21611051 is about 278.5428165473.

Adding to 21611051 its reverse (15011612), we get a palindrome (36622663).

The spelling of 21611051 in words is "twenty-one million, six hundred eleven thousand, fifty-one".