278920959781 has 4 divisors (see below), whose sum is σ = 279265733100. Its totient is φ = 278576186464.

The previous prime is 278920959769. The next prime is 278920959797. The reversal of 278920959781 is 187959029872.

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 231106140225 + 47814819556 = 480735^2 + 218666^2 .

It is a cyclic number.

It is not a de Polignac number, because 278920959781 - 2¹⁷ = 278920828709 is a prime.

It is a super-2 number, since 2×278920959781² (a number of 24 digits) 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 (278920959731) 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, 172385446 + ... + 172387063.

It is an arithmetic number, because the mean of its divisors is an integer number (69816433275).

Almost surely, 2^278920959781 is an apocalyptic number.

It is an amenable number.

278920959781 is a deficient number, since it is larger than the sum of its proper divisors (344773319).

278920959781 is an equidigital number, since it uses as much as digits as its factorization.

278920959781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 344773318.

The product of its (nonzero) digits is 45722880, while the sum is 67.

The spelling of 278920959781 in words is "two hundred seventy-eight billion, nine hundred twenty million, nine hundred fifty-nine thousand, seven hundred eighty-one".