20011999 has 8 divisors (see below), whose sum is σ = 23012480. Its totient is φ = 17046936.

The previous prime is 20011993. The next prime is 20012011. The reversal of 20011999 is 99911002.

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 20011999 - 2⁵ = 20011967 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20011999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20011993) 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, 7629 + ... + 9910.

It is an arithmetic number, because the mean of its divisors is an integer number (2876560).

Almost surely, 2^20011999 is an apocalyptic number.

20011999 is a deficient number, since it is larger than the sum of its proper divisors (3000481).

20011999 is a wasteful number, since it uses less digits than its factorization.

20011999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17709.

The product of its (nonzero) digits is 1458, while the sum is 31.

The square root of 20011999 is about 4473.4772828304. The cubic root of 20011999 is about 271.4960346355.

The spelling of 20011999 in words is "twenty million, eleven thousand, nine hundred ninety-nine".