1516165381 has 2 divisors, whose sum is σ = 1516165382. Its totient is φ = 1516165380.

The previous prime is 1516165379. The next prime is 1516165487. The reversal of 1516165381 is 1835616151.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1241434756 + 274730625 = 35234^2 + 16575^2 .

It is a cyclic number.

It is not a de Polignac number, because 1516165381 - 2¹ = 1516165379 is a prime.

It is a super-4 number, since 4×1516165381⁴ (a number of 38 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

Together with 1516165379, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1516165381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1516165331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 758082690 + 758082691.

It is an arithmetic number, because the mean of its divisors is an integer number (758082691).

Almost surely, 2^1516165381 is an apocalyptic number.

It is an amenable number.

1516165381 is a deficient number, since it is larger than the sum of its proper divisors (1).

1516165381 is an equidigital number, since it uses as much as digits as its factorization.

1516165381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21600, while the sum is 37.

The square root of 1516165381 is about 38937.9683727849. The cubic root of 1516165381 is about 1148.8117230676.

The spelling of 1516165381 in words is "one billion, five hundred sixteen million, one hundred sixty-five thousand, three hundred eighty-one".