21594712973 has 2 divisors, whose sum is σ = 21594712974. Its totient is φ = 21594712972.

The previous prime is 21594712969. The next prime is 21594712981. The reversal of 21594712973 is 37921749512.

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., 16544905129 + 5049807844 = 128627^2 + 71062^2 .

It is a cyclic number.

It is not a de Polignac number, because 21594712973 - 2² = 21594712969 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21594717973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10797356486 + 10797356487.

It is an arithmetic number, because the mean of its divisors is an integer number (10797356487).

Almost surely, 2^21594712973 is an apocalyptic number.

It is an amenable number.

21594712973 is a deficient number, since it is larger than the sum of its proper divisors (1).

21594712973 is an equidigital number, since it uses as much as digits as its factorization.

21594712973 is an evil number, because the sum of its binary digits is even.

The product of its digits is 952560, while the sum is 50.

The spelling of 21594712973 in words is "twenty-one billion, five hundred ninety-four million, seven hundred twelve thousand, nine hundred seventy-three".