2116645301581 has 2 divisors, whose sum is σ = 2116645301582. Its totient is φ = 2116645301580.

The previous prime is 2116645301569. The next prime is 2116645301657. The reversal of 2116645301581 is 1851035466112.

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., 1770254199081 + 346391102500 = 1330509^2 + 588550^2 .

It is a cyclic number.

It is not a de Polignac number, because 2116645301581 - 2³⁵ = 2082285563213 is a prime.

It is a super-2 number, since 2×2116645301581² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2116645301531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1058322650790 + 1058322650791.

It is an arithmetic number, because the mean of its divisors is an integer number (1058322650791).

Almost surely, 2^{2116645301581} is an apocalyptic number.

It is an amenable number.

2116645301581 is a deficient number, since it is larger than the sum of its proper divisors (1).

2116645301581 is an equidigital number, since it uses as much as digits as its factorization.

2116645301581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 172800, while the sum is 43.

The spelling of 2116645301581 in words is "two trillion, one hundred sixteen billion, six hundred forty-five million, three hundred one thousand, five hundred eighty-one".