261547475977 has 2 divisors, whose sum is σ = 261547475978. Its totient is φ = 261547475976.

The previous prime is 261547475941. The next prime is 261547476023. The reversal of 261547475977 is 779574745162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 202586409216 + 58961066761 = 450096^2 + 242819^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261547475977 is a prime.

It is not a weakly prime, because it can be changed into another prime (261547475927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130773737988 + 130773737989.

It is an arithmetic number, because the mean of its divisors is an integer number (130773737989).

Almost surely, 2^261547475977 is an apocalyptic number.

It is an amenable number.

261547475977 is a deficient number, since it is larger than the sum of its proper divisors (1).

261547475977 is an equidigital number, since it uses as much as digits as its factorization.

261547475977 is an evil number, because the sum of its binary digits is even.

The product of its digits is 103723200, while the sum is 64.

The spelling of 261547475977 in words is "two hundred sixty-one billion, five hundred forty-seven million, four hundred seventy-five thousand, nine hundred seventy-seven".