20400203 has 4 divisors (see below), whose sum is σ = 20416968. Its totient is φ = 20383440.

The previous prime is 20400197. The next prime is 20400239. The reversal of 20400203 is 30200402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 30200402 = 2 ⋅15100201.

It is a cyclic number.

It is not a de Polignac number, because 20400203 - 2⁸ = 20399947 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20400803) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6401 + ... + 9042.

It is an arithmetic number, because the mean of its divisors is an integer number (5104242).

Almost surely, 2^20400203 is an apocalyptic number.

20400203 is a deficient number, since it is larger than the sum of its proper divisors (16765).

20400203 is a wasteful number, since it uses less digits than its factorization.

20400203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16764.

The product of its (nonzero) digits is 48, while the sum is 11.

The square root of 20400203 is about 4516.6583886763. The cubic root of 20400203 is about 273.2403479399.

Adding to 20400203 its reverse (30200402), we get a palindrome (50600605).

The spelling of 20400203 in words is "twenty million, four hundred thousand, two hundred three".