20999999999999 has 8 divisors (see below), whose sum is σ = 22235528302128. Its totient is φ = 19764497718400.

The previous prime is 20999999999987. The next prime is 21000000000013. The reversal of 20999999999999 is 99999999999902.

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

It is a cyclic number.

It is not a de Polignac number, because 20999999999999 - 2²⁴ = 20999983222783 is a prime.

It is a super-9 number, since 9×20999999999999⁹ (a number of 121 digits) contains 999999999 as substring.

It is a Duffinian number.

20999999999999 is a modest number, since divided by 9999999 gives 2099999 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 20999999999999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20999999999599) 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, 4831232 + ... + 8083365.

It is an arithmetic number, because the mean of its divisors is an integer number (2779441037766).

Almost surely, 2^{20999999999999} is an apocalyptic number.

20999999999999 is a deficient number, since it is larger than the sum of its proper divisors (1235528302129).

20999999999999 is a wasteful number, since it uses less digits than its factorization.

20999999999999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13010265.

The product of its (nonzero) digits is 564859072962, while the sum is 110.

The spelling of 20999999999999 in words is "twenty trillion, nine hundred ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred ninety-nine".