877639661 has 2 divisors, whose sum is σ = 877639662. Its totient is φ = 877639660.

The previous prime is 877639649. The next prime is 877639717. The reversal of 877639661 is 166936778.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 781482025 + 96157636 = 27955^2 + 9806^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-877639661 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (877659661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 438819830 + 438819831.

It is an arithmetic number, because the mean of its divisors is an integer number (438819831).

Almost surely, 2^877639661 is an apocalyptic number.

It is an amenable number.

877639661 is a deficient number, since it is larger than the sum of its proper divisors (1).

877639661 is an equidigital number, since it uses as much as digits as its factorization.

877639661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2286144, while the sum is 53.

The square root of 877639661 is about 29624.9837299533. The cubic root of 877639661 is about 957.4264334128.

The spelling of 877639661 in words is "eight hundred seventy-seven million, six hundred thirty-nine thousand, six hundred sixty-one".