21152555343245 has 4 divisors (see below), whose sum is σ = 25383066411900. Its totient is φ = 16922044274592.

The previous prime is 21152555343211. The next prime is 21152555343251. The reversal of 21152555343245 is 54234355525112.

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 6368945600329 + 14783609742916 = 2523677^2 + 3844946^2 .

It is a cyclic number.

It is not a de Polignac number, because 21152555343245 - 2⁴⁰ = 20053043715469 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21152555343245.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2115255534320 + ... + 2115255534329.

It is an arithmetic number, because the mean of its divisors is an integer number (6345766602975).

Almost surely, 2^{21152555343245} is an apocalyptic number.

It is an amenable number.

21152555343245 is a deficient number, since it is larger than the sum of its proper divisors (4230511068655).

21152555343245 is an equidigital number, since it uses as much as digits as its factorization.

21152555343245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4230511068654.

The product of its digits is 3600000, while the sum is 47.

The spelling of 21152555343245 in words is "twenty-one trillion, one hundred fifty-two billion, five hundred fifty-five million, three hundred forty-three thousand, two hundred forty-five".