21911949 has 24 divisors (see below), whose sum is σ = 32752512. Its totient is φ = 14108640.

The previous prime is 21911909. The next prime is 21911957. The reversal of 21911949 is 94911912.

It is not a de Polignac number, because 21911949 - 2¹⁹ = 21387661 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21911909) 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 23 ways as a sum of consecutive naturals, for example, 33544 + ... + 34190.

It is an arithmetic number, because the mean of its divisors is an integer number (1364688).

Almost surely, 2^21911949 is an apocalyptic number.

It is an amenable number.

21911949 is a deficient number, since it is larger than the sum of its proper divisors (10840563).

21911949 is a wasteful number, since it uses less digits than its factorization.

21911949 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 777 (or 774 counting only the distinct ones).

The product of its digits is 5832, while the sum is 36.

The square root of 21911949 is about 4681.0200811362. The cubic root of 21911949 is about 279.8296114705.

The spelling of 21911949 in words is "twenty-one million, nine hundred eleven thousand, nine hundred forty-nine".