21231309999 has 16 divisors (see below), whose sum is σ = 28710237024. Its totient is φ = 13953484800.

The previous prime is 21231309991. The next prime is 21231310021. The reversal of 21231309999 is 99990313212.

It is not a de Polignac number, because 21231309999 - 2³ = 21231309991 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231309991) 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, 446239 + ... + 491519.

It is an arithmetic number, because the mean of its divisors is an integer number (1794389814).

Almost surely, 2^21231309999 is an apocalyptic number.

21231309999 is a deficient number, since it is larger than the sum of its proper divisors (7478927025).

21231309999 is a wasteful number, since it uses less digits than its factorization.

21231309999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47498.

The product of its (nonzero) digits is 236196, while the sum is 48.

The spelling of 21231309999 in words is "twenty-one billion, two hundred thirty-one million, three hundred nine thousand, nine hundred ninety-nine".