21001020122122 has 16 divisors (see below), whose sum is σ = 31786671466440. Its totient is φ = 10405500198912.

The previous prime is 21001020122113. The next prime is 21001020122141. The reversal of 21001020122122 is 22122102010012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 7253320853601 + 13747699268521 = 2693199^2 + 3707789^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21001020122096 and 21001020122105.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8177097 + ... + 10433932.

Almost surely, 2^{21001020122122} is an apocalyptic number.

21001020122122 is a deficient number, since it is larger than the sum of its proper divisors (10785651344318).

21001020122122 is a wasteful number, since it uses less digits than its factorization.

21001020122122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18616137.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21001020122122 its reverse (22122102010012), we get a palindrome (43123122132134).

The spelling of 21001020122122 in words is "twenty-one trillion, one billion, twenty million, one hundred twenty-two thousand, one hundred twenty-two".