21102120102 has 32 divisors (see below), whose sum is σ = 48613220352. Its totient is φ = 5981701824.

The previous prime is 21102120101. The next prime is 21102120107. The reversal of 21102120102 is 20102120112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102120101) 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 in 15 ways as a sum of consecutive naturals, for example, 1972743 + ... + 1983410.

It is an arithmetic number, because the mean of its divisors is an integer number (1519163136).

Almost surely, 2^21102120102 is an apocalyptic number.

21102120102 is an abundant number, since it is smaller than the sum of its proper divisors (27511100250).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21102120102 is a wasteful number, since it uses less digits than its factorization.

21102120102 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3956292.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21102120102 its reverse (20102120112), we get a palindrome (41204240214).

It can be divided in two parts, 2110 and 2120102, that added together give a palindrome (2122212).

The spelling of 21102120102 in words is "twenty-one billion, one hundred two million, one hundred twenty thousand, one hundred two".