81436961 has 2 divisors, whose sum is σ = 81436962. Its totient is φ = 81436960.

The previous prime is 81436937. The next prime is 81436967. The reversal of 81436961 is 16963418.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72250000 + 9186961 = 8500^2 + 3031^2 .

It is a cyclic number.

It is not a de Polignac number, because 81436961 - 2⁶ = 81436897 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (81436967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40718480 + 40718481.

It is an arithmetic number, because the mean of its divisors is an integer number (40718481).

Almost surely, 2^81436961 is an apocalyptic number.

It is an amenable number.

81436961 is a deficient number, since it is larger than the sum of its proper divisors (1).

81436961 is an equidigital number, since it uses as much as digits as its factorization.

81436961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 38.

The square root of 81436961 is about 9024.2429599385. The cubic root of 81436961 is about 433.4515093205.

The spelling of 81436961 in words is "eighty-one million, four hundred thirty-six thousand, nine hundred sixty-one".