21210020122 has 4 divisors (see below), whose sum is σ = 31815030186. Its totient is φ = 10605010060.

The previous prime is 21210020053. The next prime is 21210020129. The reversal of 21210020122 is 22102001212.

It is a happy number.

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., 14515671361 + 6694348761 = 120481^2 + 81819^2 .

It is not an unprimeable number, because it can be changed into a prime (21210020129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5302505029 + ... + 5302505032.

Almost surely, 2^21210020122 is an apocalyptic number.

21210020122 is a deficient number, since it is larger than the sum of its proper divisors (10605010064).

21210020122 is a wasteful number, since it uses less digits than its factorization.

21210020122 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10605010063.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21210020122 its reverse (22102001212), we get a palindrome (43312021334).

The spelling of 21210020122 in words is "twenty-one billion, two hundred ten million, twenty thousand, one hundred twenty-two".