247870891 has 4 divisors (see below), whose sum is σ = 247905000. Its totient is φ = 247836784.

The previous prime is 247870873. The next prime is 247870901. The reversal of 247870891 is 198078742.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 198078742 = 2 ⋅99039371.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-247870891 is a prime.

It is a super-2 number, since 2×247870891² = 122879957210267762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (247870391) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1306 + ... + 22303.

It is an arithmetic number, because the mean of its divisors is an integer number (61976250).

Almost surely, 2^247870891 is an apocalyptic number.

247870891 is a deficient number, since it is larger than the sum of its proper divisors (34109).

247870891 is a wasteful number, since it uses less digits than its factorization.

247870891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34108.

The product of its (nonzero) digits is 225792, while the sum is 46.

The square root of 247870891 is about 15743.9159995218. The cubic root of 247870891 is about 628.1670845329.

The spelling of 247870891 in words is "two hundred forty-seven million, eight hundred seventy thousand, eight hundred ninety-one".