21312543499 has 16 divisors (see below), whose sum is σ = 23656860864. Its totient is φ = 19078012800.

The previous prime is 21312543491. The next prime is 21312543517. The reversal of 21312543499 is 99434521312.

It is a cyclic number.

It is not a de Polignac number, because 21312543499 - 2³ = 21312543491 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21312543491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 132964 + ... + 245569.

It is an arithmetic number, because the mean of its divisors is an integer number (1478553804).

Almost surely, 2^21312543499 is an apocalyptic number.

21312543499 is a deficient number, since it is larger than the sum of its proper divisors (2344317365).

21312543499 is a wasteful number, since it uses less digits than its factorization.

21312543499 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 378678.

The product of its digits is 233280, while the sum is 43.

The spelling of 21312543499 in words is "twenty-one billion, three hundred twelve million, five hundred forty-three thousand, four hundred ninety-nine".