21001221122 has 16 divisors (see below), whose sum is σ = 36037448640. Its totient is φ = 8991684528.

The previous prime is 21001221121. The next prime is 21001221181. The reversal of 21001221122 is 22112210012.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a junction number, because it is equal to n+sod(n) for n = 21001221097 and 21001221106.

It is not an unprimeable number, because it can be changed into a prime (21001221121) 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, 721793 + ... + 750324.

It is an arithmetic number, because the mean of its divisors is an integer number (2252340540).

Almost surely, 2^21001221122 is an apocalyptic number.

21001221122 is a deficient number, since it is larger than the sum of its proper divisors (15036227518).

21001221122 is a wasteful number, since it uses less digits than its factorization.

21001221122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1473145.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21001221122 its reverse (22112210012), we get a palindrome (43113431134).

The spelling of 21001221122 in words is "twenty-one billion, one million, two hundred twenty-one thousand, one hundred twenty-two".