1000987391 has 4 divisors (see below), whose sum is σ = 1002507000. Its totient is φ = 999467784.

The previous prime is 1000987373. The next prime is 1000987417. The reversal of 1000987391 is 1937890001.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1937890001 = 23 ⋅84256087.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1000987391 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1000987331) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 758816 + ... + 760133.

It is an arithmetic number, because the mean of its divisors is an integer number (250626750).

Almost surely, 2^1000987391 is an apocalyptic number.

1000987391 is a deficient number, since it is larger than the sum of its proper divisors (1519609).

1000987391 is an equidigital number, since it uses as much as digits as its factorization.

1000987391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1519608.

The product of its (nonzero) digits is 13608, while the sum is 38.

The square root of 1000987391 is about 31638.3847722983. The cubic root of 1000987391 is about 1000.3290220659.

The spelling of 1000987391 in words is "one billion, nine hundred eighty-seven thousand, three hundred ninety-one".