21573822 has 16 divisors (see below), whose sum is σ = 43879680. Its totient is φ = 7069272.

The previous prime is 21573803. The next prime is 21573829. The reversal of 21573822 is 22837512.

It is a self number, because there is not a number n which added to its sum of digits gives 21573822.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21573829) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30118 + ... + 30825.

It is an arithmetic number, because the mean of its divisors is an integer number (2742480).

Almost surely, 2^21573822 is an apocalyptic number.

21573822 is an abundant number, since it is smaller than the sum of its proper divisors (22305858).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21573822 is a wasteful number, since it uses less digits than its factorization.

21573822 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61007.

The product of its digits is 6720, while the sum is 30.

The square root of 21573822 is about 4644.7628572404. The cubic root of 21573822 is about 278.3827775794.

The spelling of 21573822 in words is "twenty-one million, five hundred seventy-three thousand, eight hundred twenty-two".