20400400343 has 4 divisors (see below), whose sum is σ = 20514369240. Its totient is φ = 20286431448.

The previous prime is 20400400331. The next prime is 20400400379. The reversal of 20400400343 is 34300400402.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34300400402 = 2 ⋅17150200201.

It is a cyclic number.

It is not a de Polignac number, because 20400400343 - 2²⁸ = 20131964887 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 (20400420343) 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, 56984180 + ... + 56984537.

It is an arithmetic number, because the mean of its divisors is an integer number (5128592310).

Almost surely, 2^20400400343 is an apocalyptic number.

20400400343 is a deficient number, since it is larger than the sum of its proper divisors (113968897).

20400400343 is a wasteful number, since it uses less digits than its factorization.

20400400343 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113968896.

The product of its (nonzero) digits is 1152, while the sum is 20.

Adding to 20400400343 its reverse (34300400402), we get a palindrome (54700800745).

The spelling of 20400400343 in words is "twenty billion, four hundred million, four hundred thousand, three hundred forty-three".