20331687 has 4 divisors (see below), whose sum is σ = 27108920. Its totient is φ = 13554456.

The previous prime is 20331679. The next prime is 20331721. The reversal of 20331687 is 78613302.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 20331687 - 2³ = 20331679 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20331617) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3388612 + ... + 3388617.

It is an arithmetic number, because the mean of its divisors is an integer number (6777230).

Almost surely, 2^20331687 is an apocalyptic number.

20331687 is a deficient number, since it is larger than the sum of its proper divisors (6777233).

20331687 is an equidigital number, since it uses as much as digits as its factorization.

20331687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6777232.

The product of its (nonzero) digits is 6048, while the sum is 30.

The square root of 20331687 is about 4509.0671984347. The cubic root of 20331687 is about 272.9341036998.

Adding to 20331687 its reverse (78613302), we get a palindrome (98944989).

The spelling of 20331687 in words is "twenty million, three hundred thirty-one thousand, six hundred eighty-seven".