661834 has 4 divisors (see below), whose sum is σ = 992754. Its totient is φ = 330916.

The previous prime is 661823. The next prime is 661849. The reversal of 661834 is 438166.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 438166 = 2 ⋅219083.

It can be written as a sum of positive squares in only one way, i.e., 570025 + 91809 = 755^2 + 303^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165457 + ... + 165460.

2⁶⁶¹⁸³⁴ is an apocalyptic number.

661834 is a deficient number, since it is larger than the sum of its proper divisors (330920).

661834 is a wasteful number, since it uses less digits than its factorization.

661834 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330919.

The product of its digits is 3456, while the sum is 28.

The square root of 661834 is about 813.5318063850. The cubic root of 661834 is about 87.1464481954.

Subtracting from 661834 its product of digits (3456), we obtain a triangular number (658378 = T₁₁₄₇).

The spelling of 661834 in words is "six hundred sixty-one thousand, eight hundred thirty-four".