20659906 has 4 divisors (see below), whose sum is σ = 30989862. Its totient is φ = 10329952.

The previous prime is 20659901. The next prime is 20659927. The reversal of 20659906 is 60995602.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 60995602 = 2 ⋅30497801.

It can be written as a sum of positive squares in only one way, i.e., 17015625 + 3644281 = 4125^2 + 1909^2 .

It is not an unprimeable number, because it can be changed into a prime (20659901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5164975 + ... + 5164978.

Almost surely, 2^20659906 is an apocalyptic number.

20659906 is a deficient number, since it is larger than the sum of its proper divisors (10329956).

20659906 is a wasteful number, since it uses less digits than its factorization.

20659906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10329955.

The product of its (nonzero) digits is 29160, while the sum is 37.

The square root of 20659906 is about 4545.3169306441. The cubic root of 20659906 is about 274.3949496445.

The spelling of 20659906 in words is "twenty million, six hundred fifty-nine thousand, nine hundred six".