261161977 has 2 divisors, whose sum is σ = 261161978. Its totient is φ = 261161976.

The previous prime is 261161969. The next prime is 261162017. The reversal of 261161977 is 779161162.

It is an a-pointer prime, because the next prime (261162017) can be obtained adding 261161977 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 189860841 + 71301136 = 13779^2 + 8444^2 .

It is a cyclic number.

It is not a de Polignac number, because 261161977 - 2³ = 261161969 is a prime.

It is not a weakly prime, because it can be changed into another prime (261161177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130580988 + 130580989.

It is an arithmetic number, because the mean of its divisors is an integer number (130580989).

Almost surely, 2^261161977 is an apocalyptic number.

It is an amenable number.

261161977 is a deficient number, since it is larger than the sum of its proper divisors (1).

261161977 is an equidigital number, since it uses as much as digits as its factorization.

261161977 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31752, while the sum is 40.

The square root of 261161977 is about 16160.5067061649. The cubic root of 261161977 is about 639.1998276227.

The spelling of 261161977 in words is "two hundred sixty-one million, one hundred sixty-one thousand, nine hundred seventy-seven".