661264 has 20 divisors (see below), whose sum is σ = 1317004. Its totient is φ = 321408.

The previous prime is 661259. The next prime is 661267. The reversal of 661264 is 462166.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 291600 + 369664 = 540^2 + 608^2 .

It is not an unprimeable number, because it can be changed into a prime (661267) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34 + ... + 1150.

2⁶⁶¹²⁶⁴ is an apocalyptic number.

It is an amenable number.

661264 is a deficient number, since it is larger than the sum of its proper divisors (655740).

661264 is a wasteful number, since it uses less digits than its factorization.

661264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1162 (or 1156 counting only the distinct ones).

The product of its digits is 1728, while the sum is 25.

The square root of 661264 is about 813.1814065754. The cubic root of 661264 is about 87.1214229158.

The spelling of 661264 in words is "six hundred sixty-one thousand, two hundred sixty-four".