278223813 has 18 divisors (see below), whose sum is σ = 467492454. Its totient is φ = 158984784.

The previous prime is 278223793. The next prime is 278223823. The reversal of 278223813 is 318322872.

It is a happy number.

278223813 is a `hidden beast` number, since 278 + 2 + 2 + 381 + 3 = 666.

It can be written as a sum of positive squares in only one way, i.e., 220433409 + 57790404 = 14847^2 + 7602^2 .

It is not a de Polignac number, because 278223813 - 2⁶ = 278223749 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (278223823) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 315006 + ... + 315887.

It is an arithmetic number, because the mean of its divisors is an integer number (25971803).

Almost surely, 2^278223813 is an apocalyptic number.

It is an amenable number.

278223813 is a deficient number, since it is larger than the sum of its proper divisors (189268641).

278223813 is a wasteful number, since it uses less digits than its factorization.

278223813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 630913 (or 630903 counting only the distinct ones).

The product of its digits is 32256, while the sum is 36.

The square root of 278223813 is about 16680.0423560613. The cubic root of 278223813 is about 652.8269872084.

The spelling of 278223813 in words is "two hundred seventy-eight million, two hundred twenty-three thousand, eight hundred thirteen".