20311993 has 8 divisors (see below), whose sum is σ = 21930048. Its totient is φ = 18701904.

The previous prime is 20311981. The next prime is 20312021. The reversal of 20311993 is 39911302.

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

It is a de Polignac number, because none of the positive numbers 2^k-20311993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20311903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3996 + ... + 7522.

It is an arithmetic number, because the mean of its divisors is an integer number (2741256).

Almost surely, 2^20311993 is an apocalyptic number.

It is an amenable number.

20311993 is a deficient number, since it is larger than the sum of its proper divisors (1618055).

20311993 is a wasteful number, since it uses less digits than its factorization.

20311993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3983.

The product of its (nonzero) digits is 1458, while the sum is 28.

The square root of 20311993 is about 4506.8828473791. The cubic root of 20311993 is about 272.8459506492.

The spelling of 20311993 in words is "twenty million, three hundred eleven thousand, nine hundred ninety-three".