21911853 has 4 divisors (see below), whose sum is σ = 29215808. Its totient is φ = 14607900.

The previous prime is 21911839. The next prime is 21911887. The reversal of 21911853 is 35811912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21911853 - 2⁴ = 21911837 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21911853.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21911803) 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 3 ways as a sum of consecutive naturals, for example, 3651973 + ... + 3651978.

It is an arithmetic number, because the mean of its divisors is an integer number (7303952).

Almost surely, 2^21911853 is an apocalyptic number.

It is an amenable number.

21911853 is a deficient number, since it is larger than the sum of its proper divisors (7303955).

21911853 is an equidigital number, since it uses as much as digits as its factorization.

21911853 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7303954.

The product of its digits is 2160, while the sum is 30.

The square root of 21911853 is about 4681.0098269497. The cubic root of 21911853 is about 279.8292028094.

The spelling of 21911853 in words is "twenty-one million, nine hundred eleven thousand, eight hundred fifty-three".