661276 has 48 divisors (see below), whose sum is σ = 1532160. Its totient is φ = 241920.

The previous prime is 661267. The next prime is 661321. The reversal of 661276 is 672166.

It is a Smith number, since the sum of its digits (28) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is an unprimeable number.

661276 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5796 + ... + 5908.

It is an arithmetic number, because the mean of its divisors is an integer number (31920).

2⁶⁶¹²⁷⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661276, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (766080).

661276 is an abundant number, since it is smaller than the sum of its proper divisors (870884).

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

661276 is a wasteful number, since it uses less digits than its factorization.

661276 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154 (or 152 counting only the distinct ones).

The product of its digits is 3024, while the sum is 28.

The square root of 661276 is about 813.1887849694. The cubic root of 661276 is about 87.1219499120.

The spelling of 661276 in words is "six hundred sixty-one thousand, two hundred seventy-six".