21510243205102 has 4 divisors (see below), whose sum is σ = 32265364807656. Its totient is φ = 10755121602550.

The previous prime is 21510243205069. The next prime is 21510243205117. The reversal of 21510243205102 is 20150234201512.

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, 5377560801274 + ... + 5377560801277.

It is an arithmetic number, because the mean of its divisors is an integer number (8066341201914).

Almost surely, 2^{21510243205102} is an apocalyptic number.

21510243205102 is a deficient number, since it is larger than the sum of its proper divisors (10755121602554).

21510243205102 is a wasteful number, since it uses less digits than its factorization.

21510243205102 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10755121602553.

The product of its (nonzero) digits is 4800, while the sum is 28.

Adding to 21510243205102 its reverse (20150234201512), we get a palindrome (41660477406614).

The spelling of 21510243205102 in words is "twenty-one trillion, five hundred ten billion, two hundred forty-three million, two hundred five thousand, one hundred two".