278623 has 2 divisors, whose sum is σ = 278624. Its totient is φ = 278622.

The previous prime is 278617. The next prime is 278627. The reversal of 278623 is 326872.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 278623 - 2⁵ = 278591 is a prime.

It is a super-2 number, since 2×278623² = 155261552258, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 278591 and 278600.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (278627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 139311 + 139312.

It is an arithmetic number, because the mean of its divisors is an integer number (139312).

2²⁷⁸⁶²³ is an apocalyptic number.

278623 is a deficient number, since it is larger than the sum of its proper divisors (1).

278623 is an equidigital number, since it uses as much as digits as its factorization.

278623 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4032, while the sum is 28.

The square root of 278623 is about 527.8475158604. The cubic root of 278623 is about 65.3139056725.

It can be divided in two parts, 2786 and 23, that added together give a square (2809 = 53²).

The spelling of 278623 in words is "two hundred seventy-eight thousand, six hundred twenty-three".