20764687 has 4 divisors (see below), whose sum is σ = 20782440. Its totient is φ = 20746936.

The previous prime is 20764673. The next prime is 20764703. The reversal of 20764687 is 78646702.

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

It is a cyclic number.

It is not a de Polignac number, because 20764687 - 2¹¹ = 20762639 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20764187) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6988 + ... + 9505.

It is an arithmetic number, because the mean of its divisors is an integer number (5195610).

Almost surely, 2^20764687 is an apocalyptic number.

20764687 is a deficient number, since it is larger than the sum of its proper divisors (17753).

20764687 is a wasteful number, since it uses less digits than its factorization.

20764687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17752.

The product of its (nonzero) digits is 112896, while the sum is 40.

The square root of 20764687 is about 4556.8286120942. The cubic root of 20764687 is about 274.8580512598.

The spelling of 20764687 in words is "twenty million, seven hundred sixty-four thousand, six hundred eighty-seven".