21011031999 has 12 divisors (see below), whose sum is σ = 30479525856. Its totient is φ = 13947235872.

The previous prime is 21011031997. The next prime is 21011032027. The reversal of 21011031999 is 99913011012.

It is not a de Polignac number, because 21011031999 - 2¹ = 21011031997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011031997) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5007687 + ... + 5011880.

It is an arithmetic number, because the mean of its divisors is an integer number (2539960488).

Almost surely, 2^21011031999 is an apocalyptic number.

21011031999 is a deficient number, since it is larger than the sum of its proper divisors (9468493857).

21011031999 is a wasteful number, since it uses less digits than its factorization.

21011031999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10019806 (or 10019803 counting only the distinct ones).

The product of its (nonzero) digits is 4374, while the sum is 36.

The spelling of 21011031999 in words is "twenty-one billion, eleven million, thirty-one thousand, nine hundred ninety-nine".