21091822 has 4 divisors (see below), whose sum is σ = 31637736. Its totient is φ = 10545910.

The previous prime is 21091793. The next prime is 21091823. The reversal of 21091822 is 22819012.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21091823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5272954 + ... + 5272957.

It is an arithmetic number, because the mean of its divisors is an integer number (7909434).

Almost surely, 2^21091822 is an apocalyptic number.

21091822 is a deficient number, since it is larger than the sum of its proper divisors (10545914).

21091822 is a wasteful number, since it uses less digits than its factorization.

21091822 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10545913.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 21091822 is about 4592.5833688677. The cubic root of 21091822 is about 276.2939439931.

The spelling of 21091822 in words is "twenty-one million, ninety-one thousand, eight hundred twenty-two".