1816869961 has 2 divisors, whose sum is σ = 1816869962. Its totient is φ = 1816869960.

The previous prime is 1816869953. The next prime is 1816870007. The reversal of 1816869961 is 1699686181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1643815936 + 173054025 = 40544^2 + 13155^2 .

It is an emirp because it is prime and its reverse (1699686181) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 1966989181 and 1819896691.

It is a cyclic number.

It is not a de Polignac number, because 1816869961 - 2³ = 1816869953 is a prime.

It is not a weakly prime, because it can be changed into another prime (1816869931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 908434980 + 908434981.

It is an arithmetic number, because the mean of its divisors is an integer number (908434981).

Almost surely, 2^1816869961 is an apocalyptic number.

It is an amenable number.

1816869961 is a deficient number, since it is larger than the sum of its proper divisors (1).

1816869961 is an equidigital number, since it uses as much as digits as its factorization.

1816869961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1119744, while the sum is 55.

The square root of 1816869961 is about 42624.7576063489. The cubic root of 1816869961 is about 1220.2288294678.

The spelling of 1816869961 in words is "one billion, eight hundred sixteen million, eight hundred sixty-nine thousand, nine hundred sixty-one".