661877 has 2 divisors, whose sum is σ = 661878. Its totient is φ = 661876.

The previous prime is 661873. The next prime is 661879. The reversal of 661877 is 778166.

661877 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 654481 + 7396 = 809^2 + 86^2 .

It is a cyclic number.

It is not a de Polignac number, because 661877 - 2² = 661873 is a prime.

Together with 661879, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330938 + 330939.

It is an arithmetic number, because the mean of its divisors is an integer number (330939).

2⁶⁶¹⁸⁷⁷ is an apocalyptic number.

It is an amenable number.

661877 is a deficient number, since it is larger than the sum of its proper divisors (1).

661877 is an equidigital number, since it uses as much as digits as its factorization.

661877 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14112, while the sum is 35.

The square root of 661877 is about 813.5582339329. The cubic root of 661877 is about 87.1483354844.

The spelling of 661877 in words is "six hundred sixty-one thousand, eight hundred seventy-seven".