21640215536503 has 4 divisors (see below), whose sum is σ = 21640735638088. Its totient is φ = 21639695434920.

The previous prime is 21640215536491. The next prime is 21640215536573. The reversal of 21640215536503 is 30563551204612.

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

It is a cyclic number.

It is not a de Polignac number, because 21640215536503 - 2²⁵ = 21640181982071 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 21640215536503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21640215536573) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 259988376 + ... + 260071597.

It is an arithmetic number, because the mean of its divisors is an integer number (5410183909522).

Almost surely, 2^{21640215536503} is an apocalyptic number.

21640215536503 is a deficient number, since it is larger than the sum of its proper divisors (520101585).

21640215536503 is an equidigital number, since it uses as much as digits as its factorization.

21640215536503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 520101584.

The product of its (nonzero) digits is 648000, while the sum is 43.

The spelling of 21640215536503 in words is "twenty-one trillion, six hundred forty billion, two hundred fifteen million, five hundred thirty-six thousand, five hundred three".