21949111 has 2 divisors, whose sum is σ = 21949112. Its totient is φ = 21949110.

The previous prime is 21949097. The next prime is 21949139. The reversal of 21949111 is 11194912.

It is an a-pointer prime, because the next prime (21949139) can be obtained adding 21949111 to its sum of digits (28).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21949111 - 2¹¹ = 21947063 is a prime.

It is a Chen prime.

It is equal to p_1386280 and since 21949111 and 1386280 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21949111.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21949211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10974555 + 10974556.

It is an arithmetic number, because the mean of its divisors is an integer number (10974556).

Almost surely, 2^21949111 is an apocalyptic number.

21949111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21949111 is an equidigital number, since it uses as much as digits as its factorization.

21949111 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 28.

The square root of 21949111 is about 4684.9878334954. The cubic root of 21949111 is about 279.9877162979.

It can be divided in two parts, 2194911 and 1, that added together give a palindrome (2194912).

The spelling of 21949111 in words is "twenty-one million, nine hundred forty-nine thousand, one hundred eleven".