21497144411815 has 4 divisors (see below), whose sum is σ = 25796573294184. Its totient is φ = 17197715529448.

The previous prime is 21497144411797. The next prime is 21497144411833. The reversal of 21497144411815 is 51811444179412.

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

It is an interprime number because it is at equal distance from previous prime (21497144411797) and next prime (21497144411833).

It is a cyclic number.

It is not a de Polignac number, because 21497144411815 - 2¹⁵ = 21497144379047 is a prime.

It is a Duffinian number.

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, 2149714441177 + ... + 2149714441186.

It is an arithmetic number, because the mean of its divisors is an integer number (6449143323546).

Almost surely, 2^{21497144411815} is an apocalyptic number.

21497144411815 is a deficient number, since it is larger than the sum of its proper divisors (4299428882369).

21497144411815 is an equidigital number, since it uses as much as digits as its factorization.

21497144411815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4299428882368.

The product of its digits is 1290240, while the sum is 52.

The spelling of 21497144411815 in words is "twenty-one trillion, four hundred ninety-seven billion, one hundred forty-four million, four hundred eleven thousand, eight hundred fifteen".