278212961 has 4 divisors (see below), whose sum is σ = 299613972. Its totient is φ = 256811952.

The previous prime is 278212943. The next prime is 278212997. The reversal of 278212961 is 169212872.

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

It can be written as a sum of positive squares in 2 ways, for example, as 167857936 + 110355025 = 12956^2 + 10505^2 .

It is a cyclic number.

It is not a de Polignac number, because 278212961 - 2⁶ = 278212897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (278212261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10700486 + ... + 10700511.

It is an arithmetic number, because the mean of its divisors is an integer number (74903493).

Almost surely, 2^278212961 is an apocalyptic number.

It is an amenable number.

278212961 is a deficient number, since it is larger than the sum of its proper divisors (21401011).

278212961 is a wasteful number, since it uses less digits than its factorization.

278212961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21401010.

The product of its digits is 24192, while the sum is 38.

The square root of 278212961 is about 16679.7170539551. The cubic root of 278212961 is about 652.8184993529.

The spelling of 278212961 in words is "two hundred seventy-eight million, two hundred twelve thousand, nine hundred sixty-one".