1531987 has 2 divisors, whose sum is σ = 1531988. Its totient is φ = 1531986.

The previous prime is 1531909. The next prime is 1531991. The reversal of 1531987 is 7891351.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1531987 - 2¹⁵ = 1499219 is a prime.

It is not a weakly prime, because it can be changed into another prime (1531997) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 765993 + 765994.

It is an arithmetic number, because the mean of its divisors is an integer number (765994).

2^1531987 is an apocalyptic number.

1531987 is a deficient number, since it is larger than the sum of its proper divisors (1).

1531987 is an equidigital number, since it uses as much as digits as its factorization.

1531987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7560, while the sum is 34.

The square root of 1531987 is about 1237.7346242228. The cubic root of 1531987 is about 115.2793962623.

The spelling of 1531987 in words is "one million, five hundred thirty-one thousand, nine hundred eighty-seven".