21000120122 has 16 divisors (see below), whose sum is σ = 31626975744. Its totient is φ = 10457850000.

The previous prime is 21000120079. The next prime is 21000120157. The reversal of 21000120122 is 22102100012.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 796247 + ... + 822197.

It is an arithmetic number, because the mean of its divisors is an integer number (1976685984).

Almost surely, 2^21000120122 is an apocalyptic number.

21000120122 is a deficient number, since it is larger than the sum of its proper divisors (10626855622).

21000120122 is a wasteful number, since it uses less digits than its factorization.

21000120122 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27565.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21000120122 its reverse (22102100012), we get a palindrome (43102220134).

The spelling of 21000120122 in words is "twenty-one billion, one hundred twenty thousand, one hundred twenty-two".