21247822 has 4 divisors (see below), whose sum is σ = 31871736. Its totient is φ = 10623910.

The previous prime is 21247819. The next prime is 21247823. The reversal of 21247822 is 22874212.

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 (21247823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5311954 + ... + 5311957.

It is an arithmetic number, because the mean of its divisors is an integer number (7967934).

Almost surely, 2^21247822 is an apocalyptic number.

21247822 is a deficient number, since it is larger than the sum of its proper divisors (10623914).

21247822 is a wasteful number, since it uses less digits than its factorization.

21247822 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10623913.

The product of its digits is 3584, while the sum is 28.

The square root of 21247822 is about 4609.5359853243. The cubic root of 21247822 is about 276.9734494747.

The spelling of 21247822 in words is "twenty-one million, two hundred forty-seven thousand, eight hundred twenty-two".