21201221202102 has 12 divisors (see below), whose sum is σ = 45935979271260. Its totient is φ = 7067073734028.

The previous prime is 21201221202089. The next prime is 21201221202127. The reversal of 21201221202102 is 20120212210212.

It is a happy number.

21201221202102 is a `hidden beast` number, since 212 + 0 + 1 + 221 + 20 + 210 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 1177845622339 = 21201221202102 / (2 + 1 + 2 + 0 + 1 + 2 + 2 + 1 + 2 + 0 + 2 + 1 + 0 + 2).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 588922811152 + ... + 588922811187.

It is an arithmetic number, because the mean of its divisors is an integer number (3827998272605).

Almost surely, 2^{21201221202102} is an apocalyptic number.

21201221202102 is an abundant number, since it is smaller than the sum of its proper divisors (24734758069158).

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

21201221202102 is a wasteful number, since it uses less digits than its factorization.

21201221202102 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1177845622347 (or 1177845622344 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21201221202102 its reverse (20120212210212), we get a palindrome (41321433412314).

The spelling of 21201221202102 in words is "twenty-one trillion, two hundred one billion, two hundred twenty-one million, two hundred two thousand, one hundred two".