20319999 has 16 divisors (see below), whose sum is σ = 31241472. Its totient is φ = 11507328.

The previous prime is 20319989. The next prime is 20320007. The reversal of 20319999 is 99991302.

It is a happy number.

It is not a de Polignac number, because 20319999 - 2⁹ = 20319487 is a prime.

20319999 is a modest number, since divided by 9999 gives 2031 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 20319999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20319989) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1909 + ... + 6654.

It is an arithmetic number, because the mean of its divisors is an integer number (1952592).

Almost surely, 2^20319999 is an apocalyptic number.

20319999 is a deficient number, since it is larger than the sum of its proper divisors (10921473).

20319999 is a wasteful number, since it uses less digits than its factorization.

20319999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8686.

The product of its (nonzero) digits is 39366, while the sum is 42.

The square root of 20319999 is about 4507.7709569143. The cubic root of 20319999 is about 272.8817934761.

It can be divided in two parts, 203 and 19999, that added together give a palindrome (20202).

The spelling of 20319999 in words is "twenty million, three hundred nineteen thousand, nine hundred ninety-nine".