661075 has 12 divisors (see below), whose sum is σ = 847168. Its totient is φ = 511200.

The previous prime is 661061. The next prime is 661091. The reversal of 661075 is 570166.

It is not a de Polignac number, because 661075 - 2⁹ = 660563 is a prime.

It is a hoax number, since the sum of its digits (25) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a nialpdrome in base 7.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 349 + ... + 1201.

2⁶⁶¹⁰⁷⁵ is an apocalyptic number.

661075 is a deficient number, since it is larger than the sum of its proper divisors (186093).

661075 is a wasteful number, since it uses less digits than its factorization.

661075 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 894 (or 889 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 25.

The square root of 661075 is about 813.0651880384. The cubic root of 661075 is about 87.1131218853.

Subtracting from 661075 its reverse (570166), we obtain a palindrome (90909).

The spelling of 661075 in words is "six hundred sixty-one thousand, seventy-five".