1015987891 has 2 divisors, whose sum is σ = 1015987892. Its totient is φ = 1015987890.

The previous prime is 1015987883. The next prime is 1015987909. The reversal of 1015987891 is 1987895101.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (1987895101) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1015987891 - 2³ = 1015987883 is a prime.

It is not a weakly prime, because it can be changed into another prime (1015987871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 507993945 + 507993946.

It is an arithmetic number, because the mean of its divisors is an integer number (507993946).

Almost surely, 2^1015987891 is an apocalyptic number.

1015987891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1015987891 is an equidigital number, since it uses as much as digits as its factorization.

1015987891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 181440, while the sum is 49.

The square root of 1015987891 is about 31874.5649538939. The cubic root of 1015987891 is about 1005.3011452017.

The spelling of 1015987891 in words is "one billion, fifteen million, nine hundred eighty-seven thousand, eight hundred ninety-one".