20387842 has 4 divisors (see below), whose sum is σ = 30581766. Its totient is φ = 10193920.

The previous prime is 20387837. The next prime is 20387849. The reversal of 20387842 is 24878302.

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

It can be written as a sum of positive squares in only one way, i.e., 19175641 + 1212201 = 4379^2 + 1101^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20387798 and 20387807.

It is not an unprimeable number, because it can be changed into a prime (20387849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5096959 + ... + 5096962.

Almost surely, 2^20387842 is an apocalyptic number.

20387842 is a deficient number, since it is larger than the sum of its proper divisors (10193924).

20387842 is a wasteful number, since it uses less digits than its factorization.

20387842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10193923.

The product of its (nonzero) digits is 21504, while the sum is 34.

The square root of 20387842 is about 4515.2898024379. The cubic root of 20387842 is about 273.1851490391.

The spelling of 20387842 in words is "twenty million, three hundred eighty-seven thousand, eight hundred forty-two".