247172991 has 16 divisors (see below), whose sum is σ = 355207776. Its totient is φ = 151981056.

The previous prime is 247172929. The next prime is 247172993. The reversal of 247172991 is 199271742.

It is a de Polignac number, because none of the positive numbers 2^k-247172991 is a prime.

It is a super-2 number, since 2×247172991² = 122188974959772162, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (247172993) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 72951 + ... + 76263.

It is an arithmetic number, because the mean of its divisors is an integer number (22200486).

Almost surely, 2^247172991 is an apocalyptic number.

247172991 is a deficient number, since it is larger than the sum of its proper divisors (108034785).

247172991 is a wasteful number, since it uses less digits than its factorization.

247172991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5242.

The product of its digits is 63504, while the sum is 42.

The square root of 247172991 is about 15721.7362590777. The cubic root of 247172991 is about 627.5769790696.

The spelling of 247172991 in words is "two hundred forty-seven million, one hundred seventy-two thousand, nine hundred ninety-one".