660261 has 16 divisors (see below), whose sum is σ = 1050624. Its totient is φ = 360624.

The previous prime is 660251. The next prime is 660271. The reversal of 660261 is 162066.

It is an interprime number because it is at equal distance from previous prime (660251) and next prime (660271).

It is not a de Polignac number, because 660261 - 2⁶ = 660197 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an Ulam number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 660261.

It is not an unprimeable number, because it can be changed into a prime (660241) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 201 + ... + 1166.

It is an arithmetic number, because the mean of its divisors is an integer number (65664).

2⁶⁶⁰²⁶¹ is an apocalyptic number.

It is an amenable number.

660261 is a deficient number, since it is larger than the sum of its proper divisors (390363).

660261 is a wasteful number, since it uses less digits than its factorization.

660261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1400.

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 660261 is about 812.5644589816. The cubic root of 660261 is about 87.0773522648.

The spelling of 660261 in words is "six hundred sixty thousand, two hundred sixty-one".