261377763761 has 2 divisors, whose sum is σ = 261377763762. Its totient is φ = 261377763760.

The previous prime is 261377763727. The next prime is 261377763781. The reversal of 261377763761 is 167367773162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 132600852736 + 128776911025 = 364144^2 + 358855^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261377763761 is a prime.

It is a super-2 number, since 2×261377763761² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 261377763697 and 261377763706.

It is not a weakly prime, because it can be changed into another prime (261377763781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130688881880 + 130688881881.

It is an arithmetic number, because the mean of its divisors is an integer number (130688881881).

Almost surely, 2^261377763761 is an apocalyptic number.

It is an amenable number.

261377763761 is a deficient number, since it is larger than the sum of its proper divisors (1).

261377763761 is an equidigital number, since it uses as much as digits as its factorization.

261377763761 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9335088, while the sum is 56.

The spelling of 261377763761 in words is "two hundred sixty-one billion, three hundred seventy-seven million, seven hundred sixty-three thousand, seven hundred sixty-one".