1861664587 has 2 divisors, whose sum is σ = 1861664588. Its totient is φ = 1861664586.

The previous prime is 1861664561. The next prime is 1861664617. The reversal of 1861664587 is 7854661681.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1861664587 - 2¹⁹ = 1861140299 is a prime.

It is not a weakly prime, because it can be changed into another prime (1861664507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 930832293 + 930832294.

It is an arithmetic number, because the mean of its divisors is an integer number (930832294).

Almost surely, 2^1861664587 is an apocalyptic number.

1861664587 is a deficient number, since it is larger than the sum of its proper divisors (1).

1861664587 is an equidigital number, since it uses as much as digits as its factorization.

1861664587 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1935360, while the sum is 52.

The square root of 1861664587 is about 43147.0113333473. The cubic root of 1861664587 is about 1230.1757051746.

The spelling of 1861664587 in words is "one billion, eight hundred sixty-one million, six hundred sixty-four thousand, five hundred eighty-seven".