247939891 has 4 divisors (see below), whose sum is σ = 255937984. Its totient is φ = 239941800.

The previous prime is 247939859. The next prime is 247939897. The reversal of 247939891 is 198939742.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 247939891 - 2⁵ = 247939859 is a prime.

It is a super-2 number, since 2×247939891² = 122948379098183762, which contains 22 as substring.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (247939897) 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, 3999000 + ... + 3999061.

It is an arithmetic number, because the mean of its divisors is an integer number (63984496).

Almost surely, 2^247939891 is an apocalyptic number.

247939891 is a deficient number, since it is larger than the sum of its proper divisors (7998093).

247939891 is an equidigital number, since it uses as much as digits as its factorization.

247939891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7998092.

The product of its digits is 979776, while the sum is 52.

The square root of 247939891 is about 15746.1071697102. The cubic root of 247939891 is about 628.2253669011.

The spelling of 247939891 in words is "two hundred forty-seven million, nine hundred thirty-nine thousand, eight hundred ninety-one".