987997 has 2 divisors, whose sum is σ = 987998. Its totient is φ = 987996.

The previous prime is 987991. The next prime is 988007. The reversal of 987997 is 799789.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 881721 + 106276 = 939^2 + 326^2 .

It is an emirp because it is prime and its reverse (799789) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 987997 - 2⁷ = 987869 is a prime.

It is a super-2 number, since 2×987997² = 1952276144018, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 987997.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (987991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 493998 + 493999.

It is an arithmetic number, because the mean of its divisors is an integer number (493999).

2⁹⁸⁷⁹⁹⁷ is an apocalyptic number.

It is an amenable number.

987997 is a deficient number, since it is larger than the sum of its proper divisors (1).

987997 is an equidigital number, since it uses as much as digits as its factorization.

987997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 285768, while the sum is 49.

The square root of 987997 is about 993.9803821002. The cubic root of 987997 is about 99.5982884391.

The spelling of 987997 in words is "nine hundred eighty-seven thousand, nine hundred ninety-seven".