278857381 has 8 divisors (see below), whose sum is σ = 307627200. Its totient is φ = 250657440.

The previous prime is 278857379. The next prime is 278857391. The reversal of 278857381 is 183758872.

It is a happy number.

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

It is not a de Polignac number, because 278857381 - 2¹ = 278857379 is a prime.

It is a super-2 number, since 2×278857381² = 155522877876358322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (278857331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 141441 + ... + 143398.

It is an arithmetic number, because the mean of its divisors is an integer number (38453400).

Almost surely, 2^278857381 is an apocalyptic number.

It is an amenable number.

278857381 is a deficient number, since it is larger than the sum of its proper divisors (28769819).

278857381 is a wasteful number, since it uses less digits than its factorization.

278857381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 284939.

The product of its digits is 752640, while the sum is 49.

The square root of 278857381 is about 16699.0233546756. The cubic root of 278857381 is about 653.3221481900.

The spelling of 278857381 in words is "two hundred seventy-eight million, eight hundred fifty-seven thousand, three hundred eighty-one".