20506986 has 32 divisors (see below), whose sum is σ = 45756480. Its totient is φ = 6807888.

The previous prime is 20506979. The next prime is 20506987. The reversal of 20506986 is 68960502.

It is a self number, because there is not a number n which added to its sum of digits gives 20506986.

It is not an unprimeable number, because it can be changed into a prime (20506987) 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 15 ways as a sum of consecutive naturals, for example, 15960 + ... + 17196.

It is an arithmetic number, because the mean of its divisors is an integer number (1429890).

Almost surely, 2^20506986 is an apocalyptic number.

20506986 is an abundant number, since it is smaller than the sum of its proper divisors (25249494).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20506986 is a wasteful number, since it uses less digits than its factorization.

20506986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1555 (or 1549 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 20506986 is about 4528.4639779952. The cubic root of 20506986 is about 273.7162690659.

The spelling of 20506986 in words is "twenty million, five hundred six thousand, nine hundred eighty-six".