21221021121 has 48 divisors (see below), whose sum is σ = 30169321728. Its totient is φ = 13259635200.

The previous prime is 21221021119. The next prime is 21221021149. The reversal of 21221021121 is 12112012212.

It is not a de Polignac number, because 21221021121 - 2¹ = 21221021119 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21221021121.

It is not an unprimeable number, because it can be changed into a prime (21221021021) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 28032675 + ... + 28033431.

It is an arithmetic number, because the mean of its divisors is an integer number (628527536).

Almost surely, 2^21221021121 is an apocalyptic number.

It is an amenable number.

21221021121 is a deficient number, since it is larger than the sum of its proper divisors (8948300607).

21221021121 is a wasteful number, since it uses less digits than its factorization.

21221021121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1130 (or 1101 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21221021121 its reverse (12112012212), we get a palindrome (33333033333).

The spelling of 21221021121 in words is "twenty-one billion, two hundred twenty-one million, twenty-one thousand, one hundred twenty-one".