1861647331 has 2 divisors, whose sum is σ = 1861647332. Its totient is φ = 1861647330.

The previous prime is 1861647329. The next prime is 1861647343. The reversal of 1861647331 is 1337461681.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1861647331 - 2¹ = 1861647329 is a prime.

It is a super-2 number, since 2×1861647331² = 6931461570038847122, which contains 22 as substring.

Together with 1861647329, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1861644331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 930823665 + 930823666.

It is an arithmetic number, because the mean of its divisors is an integer number (930823666).

Almost surely, 2^1861647331 is an apocalyptic number.

1861647331 is a deficient number, since it is larger than the sum of its proper divisors (1).

1861647331 is an equidigital number, since it uses as much as digits as its factorization.

1861647331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72576, while the sum is 40.

The square root of 1861647331 is about 43146.8113653837. The cubic root of 1861647331 is about 1230.1719042791.

The spelling of 1861647331 in words is "one billion, eight hundred sixty-one million, six hundred forty-seven thousand, three hundred thirty-one".