20840938 has 4 divisors (see below), whose sum is σ = 31261410. Its totient is φ = 10420468.

The previous prime is 20840933. The next prime is 20840951. The reversal of 20840938 is 83904802.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83904802 = 2 ⋅41952401.

It can be written as a sum of positive squares in only one way, i.e., 19245769 + 1595169 = 4387^2 + 1263^2 .

It is not an unprimeable number, because it can be changed into a prime (20840933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5210233 + ... + 5210236.

Almost surely, 2^20840938 is an apocalyptic number.

20840938 is a deficient number, since it is larger than the sum of its proper divisors (10420472).

20840938 is a wasteful number, since it uses less digits than its factorization.

20840938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10420471.

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 20840938 is about 4565.1876193646. The cubic root of 20840938 is about 275.1940800765.

The spelling of 20840938 in words is "twenty million, eight hundred forty thousand, nine hundred thirty-eight".