21001010102 has 4 divisors (see below), whose sum is σ = 31501515156. Its totient is φ = 10500505050.

The previous prime is 21001010089. The next prime is 21001010159. The reversal of 21001010102 is 20101010012.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21001010102.

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, 5250252524 + ... + 5250252527.

It is an arithmetic number, because the mean of its divisors is an integer number (7875378789).

Almost surely, 2^21001010102 is an apocalyptic number.

21001010102 is a deficient number, since it is larger than the sum of its proper divisors (10500505054).

21001010102 is a wasteful number, since it uses less digits than its factorization.

21001010102 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10500505053.

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 21001010102 its reverse (20101010012), we get a palindrome (41102020114).

The spelling of 21001010102 in words is "twenty-one billion, one million, ten thousand, one hundred two".