20787937 has 4 divisors (see below), whose sum is σ = 20874436. Its totient is φ = 20701440.

The previous prime is 20787917. The next prime is 20787941. The reversal of 20787937 is 73978702.

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

It can be written as a sum of positive squares in 2 ways, for example, as 5973136 + 14814801 = 2444^2 + 3849^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20787937 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20787893 and 20787902.

It is not an unprimeable number, because it can be changed into a prime (20787917) 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, 42888 + ... + 43369.

It is an arithmetic number, because the mean of its divisors is an integer number (5218609).

Almost surely, 2^20787937 is an apocalyptic number.

It is an amenable number.

20787937 is a deficient number, since it is larger than the sum of its proper divisors (86499).

20787937 is an equidigital number, since it uses as much as digits as its factorization.

20787937 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86498.

The product of its (nonzero) digits is 148176, while the sum is 43.

The square root of 20787937 is about 4559.3790147344. The cubic root of 20787937 is about 274.9605982116.

The spelling of 20787937 in words is "twenty million, seven hundred eighty-seven thousand, nine hundred thirty-seven".