21221312122 has 4 divisors (see below), whose sum is σ = 31831968186. Its totient is φ = 10610656060.

The previous prime is 21221312087. The next prime is 21221312153. The reversal of 21221312122 is 22121312212.

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

It can be written as a sum of positive squares in only one way, i.e., 12372335361 + 8848976761 = 111231^2 + 94069^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21221312122.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5305328029 + ... + 5305328032.

Almost surely, 2^21221312122 is an apocalyptic number.

21221312122 is a deficient number, since it is larger than the sum of its proper divisors (10610656064).

21221312122 is a wasteful number, since it uses less digits than its factorization.

21221312122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10610656063.

The product of its digits is 192, while the sum is 19.

Adding to 21221312122 its reverse (22121312212), we get a palindrome (43342624334).

The spelling of 21221312122 in words is "twenty-one billion, two hundred twenty-one million, three hundred twelve thousand, one hundred twenty-two".