13539987 has 16 divisors (see below), whose sum is σ = 20390560. Its totient is φ = 8877600.

The previous prime is 13539983. The next prime is 13539991. The reversal of 13539987 is 78993531.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (13539983) and next prime (13539991).

It is not a de Polignac number, because 13539987 - 2² = 13539983 is a prime.

It is a super-3 number, since 3×13539987³ (a number of 22 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13539983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2464 + ... + 5757.

It is an arithmetic number, because the mean of its divisors is an integer number (1274410).

Almost surely, 2^13539987 is an apocalyptic number.

13539987 is a deficient number, since it is larger than the sum of its proper divisors (6850573).

13539987 is an equidigital number, since it uses as much as digits as its factorization.

13539987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8291 (or 8285 counting only the distinct ones).

The product of its digits is 204120, while the sum is 45.

The square root of 13539987 is about 3679.6721321335. The cubic root of 13539987 is about 238.3450201560.

The spelling of 13539987 in words is "thirteen million, five hundred thirty-nine thousand, nine hundred eighty-seven".