81961045 has 8 divisors (see below), whose sum is σ = 98702496. Its totient is φ = 65336016.

The previous prime is 81961043. The next prime is 81961081. The reversal of 81961045 is 54016918.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81961045 - 2¹ = 81961043 is a prime.

It is a super-2 number, since 2×81961045² = 13435225794984050, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81961045.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81961043) 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 in 7 ways as a sum of consecutive naturals, for example, 27547 + ... + 30376.

It is an arithmetic number, because the mean of its divisors is an integer number (12337812).

Almost surely, 2^81961045 is an apocalyptic number.

It is an amenable number.

81961045 is a deficient number, since it is larger than the sum of its proper divisors (16741451).

81961045 is a wasteful number, since it uses less digits than its factorization.

81961045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58211.

The product of its (nonzero) digits is 8640, while the sum is 34.

The square root of 81961045 is about 9053.2339525719. The cubic root of 81961045 is about 434.3793412260.

The spelling of 81961045 in words is "eighty-one million, nine hundred sixty-one thousand, forty-five".