677559781 has 2 divisors, whose sum is σ = 677559782. Its totient is φ = 677559780.

The previous prime is 677559749. The next prime is 677559787. The reversal of 677559781 is 187955776.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 431226756 + 246333025 = 20766^2 + 15695^2 .

It is a cyclic number.

It is not a de Polignac number, because 677559781 - 2⁵ = 677559749 is a prime.

It is a super-2 number, since 2×677559781² = 918174513657535922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (677559787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 338779890 + 338779891.

It is an arithmetic number, because the mean of its divisors is an integer number (338779891).

Almost surely, 2^677559781 is an apocalyptic number.

It is an amenable number.

677559781 is a deficient number, since it is larger than the sum of its proper divisors (1).

677559781 is an equidigital number, since it uses as much as digits as its factorization.

677559781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3704400, while the sum is 55.

The square root of 677559781 is about 26029.9785055616. The cubic root of 677559781 is about 878.3127886372.

The spelling of 677559781 in words is "six hundred seventy-seven million, five hundred fifty-nine thousand, seven hundred eighty-one".