161631058261 has 2 divisors, whose sum is σ = 161631058262. Its totient is φ = 161631058260.

The previous prime is 161631058187. The next prime is 161631058271. The reversal of 161631058261 is 162850136161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 160744864900 + 886193361 = 400930^2 + 29769^2 .

It is an emirp because it is prime and its reverse (162850136161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 161631058261 - 2¹⁷ = 161630927189 is a prime.

It is a super-2 number, since 2×161631058261² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161631058271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80815529130 + 80815529131.

It is an arithmetic number, because the mean of its divisors is an integer number (80815529131).

Almost surely, 2^161631058261 is an apocalyptic number.

It is an amenable number.

161631058261 is a deficient number, since it is larger than the sum of its proper divisors (1).

161631058261 is an equidigital number, since it uses as much as digits as its factorization.

161631058261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 51840, while the sum is 40.

The spelling of 161631058261 in words is "one hundred sixty-one billion, six hundred thirty-one million, fifty-eight thousand, two hundred sixty-one".