20400332221 has 2 divisors, whose sum is σ = 20400332222. Its totient is φ = 20400332220.

The previous prime is 20400332213. The next prime is 20400332269. The reversal of 20400332221 is 12223300402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18499808196 + 1900524025 = 136014^2 + 43595^2 .

It is a cyclic number.

It is not a de Polignac number, because 20400332221 - 2³ = 20400332213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20400332201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10200166110 + 10200166111.

It is an arithmetic number, because the mean of its divisors is an integer number (10200166111).

Almost surely, 2^20400332221 is an apocalyptic number.

It is an amenable number.

20400332221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20400332221 is an equidigital number, since it uses as much as digits as its factorization.

20400332221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 19.

Adding to 20400332221 its reverse (12223300402), we get a palindrome (32623632623).

The spelling of 20400332221 in words is "twenty billion, four hundred million, three hundred thirty-two thousand, two hundred twenty-one".