81635346961 has 33 divisors (see below), whose sum is σ = 101173218299. Its totient is φ = 65857086624.

The previous prime is 81635346941. The next prime is 81635346983. The reversal of 81635346961 is 16964353618.

The square root of 81635346961 is 285719.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 63556931025 + 18078415936 = 252105^2 + 134456^2 .

It is not a de Polignac number, because 81635346961 - 2⁵ = 81635346929 is a prime.

It is a Duffinian number.

Its product of digits (2799360) is a multiple of the sum of its prime divisors (24).

It is a junction number, because it is equal to n+sod(n) for n = 81635346899 and 81635346908.

It is not an unprimeable number, because it can be changed into a prime (81635346941) 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 in 32 ways as a sum of consecutive naturals, for example, 4802079225 + ... + 4802079241.

Almost surely, 2^81635346961 is an apocalyptic number.

81635346961 is the 285719-th square number.

81635346961 is the 142860-th centered octagonal number.

It is an amenable number.

81635346961 is a deficient number, since it is larger than the sum of its proper divisors (19537871338).

81635346961 is an frugal number, since it uses more digits than its factorization.

81635346961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104 (or 24 counting only the distinct ones).

The product of its digits is 2799360, while the sum is 52.

The spelling of 81635346961 in words is "eighty-one billion, six hundred thirty-five million, three hundred forty-six thousand, nine hundred sixty-one".