3991856587 has 2 divisors, whose sum is σ = 3991856588. Its totient is φ = 3991856586.

The previous prime is 3991856579. The next prime is 3991856621. The reversal of 3991856587 is 7856581993.

3991856587 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 3991856587 - 2³ = 3991856579 is a prime.

It is a super-2 number, since 2×3991856587² = 31869838022350577138, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (3991856527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1995928293 + 1995928294.

It is an arithmetic number, because the mean of its divisors is an integer number (1995928294).

Almost surely, 2^3991856587 is an apocalyptic number.

3991856587 is a deficient number, since it is larger than the sum of its proper divisors (1).

3991856587 is an equidigital number, since it uses as much as digits as its factorization.

3991856587 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16329600, while the sum is 61.

The square root of 3991856587 is about 63181.1410707341. The cubic root of 3991856587 is about 1586.3230815768.

The spelling of 3991856587 in words is "three billion, nine hundred ninety-one million, eight hundred fifty-six thousand, five hundred eighty-seven".