20131866 has 12 divisors (see below), whose sum is σ = 43619082. Its totient is φ = 6710616.

The previous prime is 20131819. The next prime is 20131871. The reversal of 20131866 is 66813102.

It can be written as a sum of positive squares in only one way, i.e., 20115225 + 16641 = 4485^2 + 129^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 559201 + ... + 559236.

Almost surely, 2^20131866 is an apocalyptic number.

20131866 is an abundant number, since it is smaller than the sum of its proper divisors (23487216).

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

20131866 is a wasteful number, since it uses less digits than its factorization.

20131866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1118445 (or 1118442 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 20131866 is about 4486.8548004142. The cubic root of 20131866 is about 272.0370209846.

Adding to 20131866 its reverse (66813102), we get a palindrome (86944968).

The spelling of 20131866 in words is "twenty million, one hundred thirty-one thousand, eight hundred sixty-six".