247728139 has 4 divisors (see below), whose sum is σ = 248292880. Its totient is φ = 247163400.

The previous prime is 247728127. The next prime is 247728149. The reversal of 247728139 is 931827742.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 931827742 = 2 ⋅465913871.

It is a cyclic number.

It is not a de Polignac number, because 247728139 - 2¹⁷ = 247597067 is a prime.

It is a super-2 number, since 2×247728139² = 122738461704806642, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 247728095 and 247728104.

It is not an unprimeable number, because it can be changed into a prime (247728149) 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, 281712 + ... + 282589.

It is an arithmetic number, because the mean of its divisors is an integer number (62073220).

Almost surely, 2^247728139 is an apocalyptic number.

247728139 is a deficient number, since it is larger than the sum of its proper divisors (564741).

247728139 is an equidigital number, since it uses as much as digits as its factorization.

247728139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 564740.

The product of its digits is 169344, while the sum is 43.

The square root of 247728139 is about 15739.3817858263. The cubic root of 247728139 is about 628.0464715702.

The spelling of 247728139 in words is "two hundred forty-seven million, seven hundred twenty-eight thousand, one hundred thirty-nine".