21295423789 has 2 divisors, whose sum is σ = 21295423790. Its totient is φ = 21295423788.

The previous prime is 21295423783. The next prime is 21295423817. The reversal of 21295423789 is 98732459212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20748097764 + 547326025 = 144042^2 + 23395^2 .

It is a cyclic number.

It is not a de Polignac number, because 21295423789 - 2¹³ = 21295415597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21295423783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10647711894 + 10647711895.

It is an arithmetic number, because the mean of its divisors is an integer number (10647711895).

Almost surely, 2^21295423789 is an apocalyptic number.

It is an amenable number.

21295423789 is a deficient number, since it is larger than the sum of its proper divisors (1).

21295423789 is an equidigital number, since it uses as much as digits as its factorization.

21295423789 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2177280, while the sum is 52.

The spelling of 21295423789 in words is "twenty-one billion, two hundred ninety-five million, four hundred twenty-three thousand, seven hundred eighty-nine".