21594712361 has 2 divisors, whose sum is σ = 21594712362. Its totient is φ = 21594712360.

The previous prime is 21594712339. The next prime is 21594712429. The reversal of 21594712361 is 16321749512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16825981225 + 4768731136 = 129715^2 + 69056^2 .

It is a cyclic number.

It is not a de Polignac number, because 21594712361 - 2²² = 21590518057 is a prime.

It is not a weakly prime, because it can be changed into another prime (21594742361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10797356180 + 10797356181.

It is an arithmetic number, because the mean of its divisors is an integer number (10797356181).

Almost surely, 2^21594712361 is an apocalyptic number.

It is an amenable number.

21594712361 is a deficient number, since it is larger than the sum of its proper divisors (1).

21594712361 is an equidigital number, since it uses as much as digits as its factorization.

21594712361 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90720, while the sum is 41.

The spelling of 21594712361 in words is "twenty-one billion, five hundred ninety-four million, seven hundred twelve thousand, three hundred sixty-one".