20803906 has 4 divisors (see below), whose sum is σ = 31205862. Its totient is φ = 10401952.

The previous prime is 20803901. The next prime is 20803907. The reversal of 20803906 is 60930802.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 60930802 = 2 ⋅30465401.

It can be written as a sum of positive squares in only one way, i.e., 15673681 + 5130225 = 3959^2 + 2265^2 .

It is not an unprimeable number, because it can be changed into a prime (20803901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5200975 + ... + 5200978.

Almost surely, 2^20803906 is an apocalyptic number.

20803906 is a deficient number, since it is larger than the sum of its proper divisors (10401956).

20803906 is a wasteful number, since it uses less digits than its factorization.

20803906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10401955.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 20803906 is about 4561.1299038725. The cubic root of 20803906 is about 275.0309871418.

The spelling of 20803906 in words is "twenty million, eight hundred three thousand, nine hundred six".