21020212102 has 4 divisors (see below), whose sum is σ = 31530318156. Its totient is φ = 10510106050.

The previous prime is 21020212099. The next prime is 21020212111. The reversal of 21020212102 is 20121202012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5255053024 + ... + 5255053027.

It is an arithmetic number, because the mean of its divisors is an integer number (7882579539).

Almost surely, 2^21020212102 is an apocalyptic number.

21020212102 is a deficient number, since it is larger than the sum of its proper divisors (10510106054).

21020212102 is a wasteful number, since it uses less digits than its factorization.

21020212102 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10510106053.

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

Adding to 21020212102 its reverse (20121202012), we get a palindrome (41141414114).

The spelling of 21020212102 in words is "twenty-one billion, twenty million, two hundred twelve thousand, one hundred two".