81147961 has 2 divisors, whose sum is σ = 81147962. Its totient is φ = 81147960.

The previous prime is 81147949. The next prime is 81147973. The reversal of 81147961 is 16974118.

It is a balanced prime because it is at equal distance from previous prime (81147949) and next prime (81147973).

It can be written as a sum of positive squares in only one way, i.e., 62173225 + 18974736 = 7885^2 + 4356^2 .

It is a cyclic number.

It is not a de Polignac number, because 81147961 - 2⁹ = 81147449 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81147961.

It is not a weakly prime, because it can be changed into another prime (81147061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40573980 + 40573981.

It is an arithmetic number, because the mean of its divisors is an integer number (40573981).

Almost surely, 2^81147961 is an apocalyptic number.

It is an amenable number.

81147961 is a deficient number, since it is larger than the sum of its proper divisors (1).

81147961 is an equidigital number, since it uses as much as digits as its factorization.

81147961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12096, while the sum is 37.

The square root of 81147961 is about 9008.2163051294. The cubic root of 81147961 is about 432.9381635424.

The spelling of 81147961 in words is "eighty-one million, one hundred forty-seven thousand, nine hundred sixty-one".