13987531 has 2 divisors, whose sum is σ = 13987532. Its totient is φ = 13987530.

The previous prime is 13987489. The next prime is 13987537. The reversal of 13987531 is 13578931.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 13987531 - 2⁷ = 13987403 is a prime.

It is a super-2 number, since 2×13987531² = 391302046951922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (13987537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6993765 + 6993766.

It is an arithmetic number, because the mean of its divisors is an integer number (6993766).

Almost surely, 2^13987531 is an apocalyptic number.

13987531 is a deficient number, since it is larger than the sum of its proper divisors (1).

13987531 is an equidigital number, since it uses as much as digits as its factorization.

13987531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22680, while the sum is 37.

The square root of 13987531 is about 3739.9907753897. The cubic root of 13987531 is about 240.9426526313.

The spelling of 13987531 in words is "thirteen million, nine hundred eighty-seven thousand, five hundred thirty-one".