661278 has 16 divisors (see below), whose sum is σ = 1330560. Its totient is φ = 219096.

The previous prime is 661267. The next prime is 661321. The reversal of 661278 is 872166.

It is a happy number.

661278 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1663 + ... + 2021.

It is an arithmetic number, because the mean of its divisors is an integer number (83160).

2⁶⁶¹²⁷⁸ is an apocalyptic number.

661278 is an abundant number, since it is smaller than the sum of its proper divisors (669282).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661278 is a wasteful number, since it uses less digits than its factorization.

661278 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 671.

The product of its digits is 4032, while the sum is 30.

The square root of 661278 is about 813.1900146952. The cubic root of 661278 is about 87.1220377441.

It can be divided in two parts, 661 and 278, that added together give a palindrome (939).

The spelling of 661278 in words is "six hundred sixty-one thousand, two hundred seventy-eight".