247138491 has 8 divisors (see below), whose sum is σ = 346861120. Its totient is φ = 156087432.

The previous prime is 247138471. The next prime is 247138499. The reversal of 247138491 is 194831742.

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

It is not a de Polignac number, because 247138491 - 2²¹ = 245041339 is a prime.

It is a super-2 number, since 2×247138491² = 122154867467514162, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (247138499) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2167825 + ... + 2167938.

It is an arithmetic number, because the mean of its divisors is an integer number (43357640).

Almost surely, 2^247138491 is an apocalyptic number.

247138491 is a deficient number, since it is larger than the sum of its proper divisors (99722629).

247138491 is a wasteful number, since it uses less digits than its factorization.

247138491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4335785.

The product of its digits is 48384, while the sum is 39.

The square root of 247138491 is about 15720.6390137297. The cubic root of 247138491 is about 627.5477789897.

The spelling of 247138491 in words is "two hundred forty-seven million, one hundred thirty-eight thousand, four hundred ninety-one".