21000131999 has 32 divisors (see below), whose sum is σ = 26875279872. Its totient is φ = 15935760000.

The previous prime is 21000131989. The next prime is 21000132029. The reversal of 21000131999 is 99913100012.

It is a cyclic number.

It is not a de Polignac number, because 21000131999 - 2⁴ = 21000131983 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000131989) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 452264 + ... + 496530.

It is an arithmetic number, because the mean of its divisors is an integer number (839852496).

Almost surely, 2^21000131999 is an apocalyptic number.

21000131999 is a deficient number, since it is larger than the sum of its proper divisors (5875147873).

21000131999 is a wasteful number, since it uses less digits than its factorization.

21000131999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44447.

The product of its (nonzero) digits is 4374, while the sum is 35.

It can be divided in two parts, 2100013 and 1999, that added together give a palindrome (2102012).

The spelling of 21000131999 in words is "twenty-one billion, one hundred thirty-one thousand, nine hundred ninety-nine".