661670 has 16 divisors (see below), whose sum is σ = 1202688. Its totient is φ = 262080.

The previous prime is 661663. The next prime is 661673. The reversal of 661670 is 76166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661673) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1010 + ... + 1530.

It is an arithmetic number, because the mean of its divisors is an integer number (75168).

2⁶⁶¹⁶⁷⁰ is an apocalyptic number.

661670 is a deficient number, since it is larger than the sum of its proper divisors (541018).

661670 is a wasteful number, since it uses less digits than its factorization.

661670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 655.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 661670 is about 813.4310050644. The cubic root of 661670 is about 87.1392494123.

It can be divided in two parts, 661 and 670, that added together give a palindrome (1331).

The spelling of 661670 in words is "six hundred sixty-one thousand, six hundred seventy".