21221522 has 8 divisors (see below), whose sum is σ = 36379776. Its totient is φ = 9094932.

The previous prime is 21221521. The next prime is 21221531. The reversal of 21221522 is 22512212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21221522.

It is not an unprimeable number, because it can be changed into a prime (21221521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 757898 + ... + 757925.

It is an arithmetic number, because the mean of its divisors is an integer number (4547472).

Almost surely, 2^21221522 is an apocalyptic number.

21221522 is a deficient number, since it is larger than the sum of its proper divisors (15158254).

21221522 is a wasteful number, since it uses less digits than its factorization.

21221522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1515832.

The product of its digits is 160, while the sum is 17.

The square root of 21221522 is about 4606.6823202821. The cubic root of 21221522 is about 276.8591254548.

Adding to 21221522 its reverse (22512212), we get a palindrome (43733734).

The spelling of 21221522 in words is "twenty-one million, two hundred twenty-one thousand, five hundred twenty-two".