1609340726821 has 2 divisors, whose sum is σ = 1609340726822. Its totient is φ = 1609340726820.

The previous prime is 1609340726797. The next prime is 1609340726837. The reversal of 1609340726821 is 1286270439061.

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., 1487633938596 + 121706788225 = 1219686^2 + 348865^2 .

It is an emirp because it is prime and its reverse (1286270439061) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1609340726821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1609340726881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 804670363410 + 804670363411.

It is an arithmetic number, because the mean of its divisors is an integer number (804670363411).

Almost surely, 2^{1609340726821} is an apocalyptic number.

It is an amenable number.

1609340726821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1609340726821 is an equidigital number, since it uses as much as digits as its factorization.

1609340726821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 870912, while the sum is 49.

The spelling of 1609340726821 in words is "one trillion, six hundred nine billion, three hundred forty million, seven hundred twenty-six thousand, eight hundred twenty-one".