631987 has 2 divisors, whose sum is σ = 631988. Its totient is φ = 631986.

The previous prime is 631979. The next prime is 631991. The reversal of 631987 is 789136.

631987 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 631987 - 2³ = 631979 is a prime.

631987 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (631927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315993 + 315994.

It is an arithmetic number, because the mean of its divisors is an integer number (315994).

2⁶³¹⁹⁸⁷ is an apocalyptic number.

631987 is a deficient number, since it is larger than the sum of its proper divisors (1).

631987 is an equidigital number, since it uses as much as digits as its factorization.

631987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9072, while the sum is 34.

The square root of 631987 is about 794.9761002697. The cubic root of 631987 is about 85.8162201301.

The spelling of 631987 in words is "six hundred thirty-one thousand, nine hundred eighty-seven".