20404643789 has 2 divisors, whose sum is σ = 20404643790. Its totient is φ = 20404643788.

The previous prime is 20404643773. The next prime is 20404643801. The reversal of 20404643789 is 98734640402.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15691821289 + 4712822500 = 125267^2 + 68650^2 .

It is a cyclic number.

It is not a de Polignac number, because 20404643789 - 2⁴ = 20404643773 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20404643719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10202321894 + 10202321895.

It is an arithmetic number, because the mean of its divisors is an integer number (10202321895).

Almost surely, 2^20404643789 is an apocalyptic number.

It is an amenable number.

20404643789 is a deficient number, since it is larger than the sum of its proper divisors (1).

20404643789 is an equidigital number, since it uses as much as digits as its factorization.

20404643789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1161216, while the sum is 47.

The spelling of 20404643789 in words is "twenty billion, four hundred four million, six hundred forty-three thousand, seven hundred eighty-nine".