20400223 has 4 divisors (see below), whose sum is σ = 20458368. Its totient is φ = 20342080.

The previous prime is 20400197. The next prime is 20400239. The reversal of 20400223 is 32200402.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20400223 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20400823) 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, 28543 + ... + 29248.

It is an arithmetic number, because the mean of its divisors is an integer number (5114592).

Almost surely, 2^20400223 is an apocalyptic number.

20400223 is a deficient number, since it is larger than the sum of its proper divisors (58145).

20400223 is an equidigital number, since it uses as much as digits as its factorization.

20400223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58144.

The product of its (nonzero) digits is 96, while the sum is 13.

The square root of 20400223 is about 4516.6606027020. The cubic root of 20400223 is about 273.2404372332.

Adding to 20400223 its reverse (32200402), we get a palindrome (52600625).

The spelling of 20400223 in words is "twenty million, four hundred thousand, two hundred twenty-three".