661774 has 4 divisors (see below), whose sum is σ = 992664. Its totient is φ = 330886.

The previous prime is 661769. The next prime is 661777. The reversal of 661774 is 477166.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165442 + ... + 165445.

It is an arithmetic number, because the mean of its divisors is an integer number (248166).

2⁶⁶¹⁷⁷⁴ is an apocalyptic number.

661774 is a deficient number, since it is larger than the sum of its proper divisors (330890).

661774 is a wasteful number, since it uses less digits than its factorization.

661774 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330889.

The product of its digits is 7056, while the sum is 31.

The square root of 661774 is about 813.4949293020. The cubic root of 661774 is about 87.1438146322.

The spelling of 661774 in words is "six hundred sixty-one thousand, seven hundred seventy-four".