20400431321 has 16 divisors (see below), whose sum is σ = 21258501840. Its totient is φ = 19552915200.

The previous prime is 20400431287. The next prime is 20400431329. The reversal of 20400431321 is 12313400402.

It can be written as a sum of positive squares in 8 ways, for example, as 4916113225 + 15484318096 = 70115^2 + 124436^2 .

It is a cyclic number.

It is not a de Polignac number, because 20400431321 - 2³⁰ = 19326689497 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20400431293 and 20400431302.

It is not an unprimeable number, because it can be changed into a prime (20400431329) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8654075 + ... + 8656431.

It is an arithmetic number, because the mean of its divisors is an integer number (1328656365).

Almost surely, 2^20400431321 is an apocalyptic number.

It is an amenable number.

20400431321 is a deficient number, since it is larger than the sum of its proper divisors (858070519).

20400431321 is a wasteful number, since it uses less digits than its factorization.

20400431321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4444.

The product of its (nonzero) digits is 576, while the sum is 20.

Adding to 20400431321 its reverse (12313400402), we get a palindrome (32713831723).

The spelling of 20400431321 in words is "twenty billion, four hundred million, four hundred thirty-one thousand, three hundred twenty-one".