661277 has 4 divisors (see below), whose sum is σ = 664800. Its totient is φ = 657756.

The previous prime is 661267. The next prime is 661321. The reversal of 661277 is 772166.

661277 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 772166 = 2 ⋅386083.

It is a cyclic number.

It is not a de Polignac number, because 661277 - 2¹⁶ = 595741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661217) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1463 + ... + 1860.

It is an arithmetic number, because the mean of its divisors is an integer number (166200).

2⁶⁶¹²⁷⁷ is an apocalyptic number.

It is an amenable number.

661277 is a deficient number, since it is larger than the sum of its proper divisors (3523).

661277 is a wasteful number, since it uses less digits than its factorization.

661277 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3522.

The product of its digits is 3528, while the sum is 29.

The square root of 661277 is about 813.1893998325. The cubic root of 661277 is about 87.1219938280.

Subtracting 661277 from its reverse (772166), we obtain a square (110889 = 333²).

The spelling of 661277 in words is "six hundred sixty-one thousand, two hundred seventy-seven".