21115502351213 has 4 divisors (see below), whose sum is σ = 21309222556380. Its totient is φ = 20921782146048.

The previous prime is 21115502351197. The next prime is 21115502351233. The reversal of 21115502351213 is 31215320551112.

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

It can be written as a sum of positive squares in 2 ways, for example, as 15377048564164 + 5738453787049 = 3921358^2 + 2395507^2 .

It is a cyclic number.

It is not a de Polignac number, because 21115502351213 - 2⁴ = 21115502351197 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21115502351213.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21115502351233) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 96860102420 + ... + 96860102637.

It is an arithmetic number, because the mean of its divisors is an integer number (5327305639095).

Almost surely, 2^{21115502351213} is an apocalyptic number.

It is an amenable number.

21115502351213 is a deficient number, since it is larger than the sum of its proper divisors (193720205167).

21115502351213 is a wasteful number, since it uses less digits than its factorization.

21115502351213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193720205166.

The product of its (nonzero) digits is 9000, while the sum is 32.

The spelling of 21115502351213 in words is "twenty-one trillion, one hundred fifteen billion, five hundred two million, three hundred fifty-one thousand, two hundred thirteen".