81260661 has 16 divisors (see below), whose sum is σ = 109866240. Its totient is φ = 53419200.

The previous prime is 81260659. The next prime is 81260671. The reversal of 81260661 is 16606218.

It is not a de Polignac number, because 81260661 - 2¹ = 81260659 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81260671) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 112660 + ... + 113378.

It is an arithmetic number, because the mean of its divisors is an integer number (6866640).

Almost surely, 2^81260661 is an apocalyptic number.

It is an amenable number.

81260661 is a deficient number, since it is larger than the sum of its proper divisors (28605579).

81260661 is a wasteful number, since it uses less digits than its factorization.

81260661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1196.

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 81260661 is about 9014.4695351418. The cubic root of 81260661 is about 433.1384953806.

Adding to 81260661 its reverse (16606218), we get a palindrome (97866879).

The spelling of 81260661 in words is "eighty-one million, two hundred sixty thousand, six hundred sixty-one".