661258 has 16 divisors (see below), whose sum is σ = 1106280. Its totient is φ = 294336.

The previous prime is 661253. The next prime is 661259. The reversal of 661258 is 852166.

It can be written as a sum of positive squares in 4 ways, for example, as 567009 + 94249 = 753^2 + 307^2 .

It is not an unprimeable number, because it can be changed into a prime (661253) 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, 316 + ... + 1192.

2⁶⁶¹²⁵⁸ is an apocalyptic number.

661258 is a deficient number, since it is larger than the sum of its proper divisors (445022).

661258 is a wasteful number, since it uses less digits than its factorization.

661258 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 921.

The product of its digits is 2880, while the sum is 28.

The square root of 661258 is about 813.1777173533. The cubic root of 661258 is about 87.1211594154.

Subtracting from 661258 its product of digits (2880), we obtain a triangular number (658378 = T₁₁₄₇).

It can be divided in two parts, 6612 and 58, that added together give a triangular number (6670 = T₁₁₅).

The spelling of 661258 in words is "six hundred sixty-one thousand, two hundred fifty-eight".