247987981 has 8 divisors (see below), whose sum is σ = 264186720. Its totient is φ = 232103952.

The previous prime is 247987973. The next prime is 247988017. The reversal of 247987981 is 189789742.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 247987981 - 2³ = 247987973 is a prime.

It is a super-2 number, since 2×247987981² = 122996077440912722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (247907981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 77050 + ... + 80203.

It is an arithmetic number, because the mean of its divisors is an integer number (33023340).

Almost surely, 2^247987981 is an apocalyptic number.

It is an amenable number.

247987981 is a deficient number, since it is larger than the sum of its proper divisors (16198739).

247987981 is a wasteful number, since it uses less digits than its factorization.

247987981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157355.

The product of its digits is 2032128, while the sum is 55.

The square root of 247987981 is about 15747.6341397684. The cubic root of 247987981 is about 628.2659807837.

The spelling of 247987981 in words is "two hundred forty-seven million, nine hundred eighty-seven thousand, nine hundred eighty-one".