21744540474487 has 4 divisors (see below), whose sum is σ = 21744551280816. Its totient is φ = 21744529668160.

The previous prime is 21744540474439. The next prime is 21744540474511. The reversal of 21744540474487 is 78447404544712.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21744540474487 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21744540474427) 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, 1392523 + ... + 6740044.

It is an arithmetic number, because the mean of its divisors is an integer number (5436137820204).

Almost surely, 2^{21744540474487} is an apocalyptic number.

21744540474487 is a deficient number, since it is larger than the sum of its proper divisors (10806329).

21744540474487 is an equidigital number, since it uses as much as digits as its factorization.

21744540474487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10806328.

The product of its (nonzero) digits is 112394240, while the sum is 61.

The spelling of 21744540474487 in words is "twenty-one trillion, seven hundred forty-four billion, five hundred forty million, four hundred seventy-four thousand, four hundred eighty-seven".