20631906 has 12 divisors (see below), whose sum is σ = 44702502. Its totient is φ = 6877296.

The previous prime is 20631899. The next prime is 20631907. The reversal of 20631906 is 60913602.

It is a happy number.

20631906 is a `hidden beast` number, since 20 + 631 + 9 + 0 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 14175225 + 6456681 = 3765^2 + 2541^2 .

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20631906.

It is not an unprimeable number, because it can be changed into a prime (20631907) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 573091 + ... + 573126.

Almost surely, 2^20631906 is an apocalyptic number.

20631906 is an abundant number, since it is smaller than the sum of its proper divisors (24070596).

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

20631906 is a wasteful number, since it uses less digits than its factorization.

20631906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1146225 (or 1146222 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 27.

The square root of 20631906 is about 4542.2357930869. The cubic root of 20631906 is about 274.2709327507.

It can be divided in two parts, 2063 and 1906, that added together give a square (3969 = 63²).

The spelling of 20631906 in words is "twenty million, six hundred thirty-one thousand, nine hundred six".