1807801661 has 2 divisors, whose sum is σ = 1807801662. Its totient is φ = 1807801660.

The previous prime is 1807801621. The next prime is 1807801663. The reversal of 1807801661 is 1661087081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1430276761 + 377524900 = 37819^2 + 19430^2 .

It is a cyclic number.

It is not a de Polignac number, because 1807801661 - 2¹⁴ = 1807785277 is a prime.

Together with 1807801663, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1807801663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 903900830 + 903900831.

It is an arithmetic number, because the mean of its divisors is an integer number (903900831).

Almost surely, 2^1807801661 is an apocalyptic number.

It is an amenable number.

1807801661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1807801661 is an equidigital number, since it uses as much as digits as its factorization.

1807801661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16128, while the sum is 38.

The square root of 1807801661 is about 42518.2509165182. The cubic root of 1807801661 is about 1218.1953208692.

The spelling of 1807801661 in words is "one billion, eight hundred seven million, eight hundred one thousand, six hundred sixty-one".