1641995081 has 2 divisors, whose sum is σ = 1641995082. Its totient is φ = 1641995080.

The previous prime is 1641995071. The next prime is 1641995111. The reversal of 1641995081 is 1805991461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1399134025 + 242861056 = 37405^2 + 15584^2 .

It is a cyclic number.

It is not a de Polignac number, because 1641995081 - 2¹⁴ = 1641978697 is a prime.

It is a super-2 number, since 2×1641995081² = 5392295692056393122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1641995071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820997540 + 820997541.

It is an arithmetic number, because the mean of its divisors is an integer number (820997541).

Almost surely, 2^1641995081 is an apocalyptic number.

It is an amenable number.

1641995081 is a deficient number, since it is larger than the sum of its proper divisors (1).

1641995081 is an equidigital number, since it uses as much as digits as its factorization.

1641995081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 77760, while the sum is 44.

The square root of 1641995081 is about 40521.5384826391. The cubic root of 1641995081 is about 1179.7517147347.

The spelling of 1641995081 in words is "one billion, six hundred forty-one million, nine hundred ninety-five thousand, eighty-one".