21011001999 has 8 divisors (see below), whose sum is σ = 30169643952. Its totient is φ = 12929847360.

The previous prime is 21011001989. The next prime is 21011002031. The reversal of 21011001999 is 99910011012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21011001999 - 2²⁸ = 20742566543 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011001919) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 269371782 + ... + 269371859.

It is an arithmetic number, because the mean of its divisors is an integer number (3771205494).

Almost surely, 2^21011001999 is an apocalyptic number.

21011001999 is a deficient number, since it is larger than the sum of its proper divisors (9158641953).

21011001999 is a wasteful number, since it uses less digits than its factorization.

21011001999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 538743657.

The product of its (nonzero) digits is 1458, while the sum is 33.

The spelling of 21011001999 in words is "twenty-one billion, eleven million, one thousand, nine hundred ninety-nine".