961505981 has 2 divisors, whose sum is σ = 961505982. Its totient is φ = 961505980.

The previous prime is 961505971. The next prime is 961505983. The reversal of 961505981 is 189505169.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 487747225 + 473758756 = 22085^2 + 21766^2 .

It is a cyclic number.

It is not a de Polignac number, because 961505981 - 2¹⁸ = 961243837 is a prime.

It is a super-2 number, since 2×961505981² = 1848987502997544722, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 961505983, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (961505983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 480752990 + 480752991.

It is an arithmetic number, because the mean of its divisors is an integer number (480752991).

Almost surely, 2^961505981 is an apocalyptic number.

It is an amenable number.

961505981 is a deficient number, since it is larger than the sum of its proper divisors (1).

961505981 is an equidigital number, since it uses as much as digits as its factorization.

961505981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 97200, while the sum is 44.

The square root of 961505981 is about 31008.1599099334. The cubic root of 961505981 is about 987.0004030784. Note that the first 3 decimals are identical.

The spelling of 961505981 in words is "nine hundred sixty-one million, five hundred five thousand, nine hundred eighty-one".