20400343 has 4 divisors (see below), whose sum is σ = 20410200. Its totient is φ = 20390488.

The previous prime is 20400337. The next prime is 20400349. The reversal of 20400343 is 34300402.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 34300402 = 2 ⋅17150201.

It is an interprime number because it is at equal distance from previous prime (20400337) and next prime (20400349).

It is a cyclic number.

It is not a de Polignac number, because 20400343 - 2⁹ = 20399831 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 (20400349) 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, 493 + ... + 6406.

It is an arithmetic number, because the mean of its divisors is an integer number (5102550).

Almost surely, 2^20400343 is an apocalyptic number.

20400343 is a deficient number, since it is larger than the sum of its proper divisors (9857).

20400343 is an equidigital number, since it uses as much as digits as its factorization.

20400343 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9856.

The product of its (nonzero) digits is 288, while the sum is 16.

The square root of 20400343 is about 4516.6738868331. The cubic root of 20400343 is about 273.2409729919.

Adding to 20400343 its reverse (34300402), we get a palindrome (54700745).

The spelling of 20400343 in words is "twenty million, four hundred thousand, three hundred forty-three".