2165138616401 has 2 divisors, whose sum is σ = 2165138616402. Its totient is φ = 2165138616400.

The previous prime is 2165138616383. The next prime is 2165138616467. The reversal of 2165138616401 is 1046168315612.

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., 1873063222801 + 292075393600 = 1368599^2 + 540440^2 .

It is a cyclic number.

It is not a de Polignac number, because 2165138616401 - 2²² = 2165134422097 is a prime.

It is not a weakly prime, because it can be changed into another prime (2165138616491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1082569308200 + 1082569308201.

It is an arithmetic number, because the mean of its divisors is an integer number (1082569308201).

Almost surely, 2^{2165138616401} is an apocalyptic number.

It is an amenable number.

2165138616401 is a deficient number, since it is larger than the sum of its proper divisors (1).

2165138616401 is an equidigital number, since it uses as much as digits as its factorization.

2165138616401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 207360, while the sum is 44.

The spelling of 2165138616401 in words is "two trillion, one hundred sixty-five billion, one hundred thirty-eight million, six hundred sixteen thousand, four hundred one".