81060640 has 24 divisors (see below), whose sum is σ = 191506140. Its totient is φ = 32424192.

The previous prime is 81060613. The next prime is 81060653. The reversal of 81060640 is 4606018.

It can be written as a sum of positive squares in 2 ways, for example, as 78357904 + 2702736 = 8852^2 + 1644^2 .

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 253155 + ... + 253474.

Almost surely, 2^81060640 is an apocalyptic number.

81060640 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81060640 is an abundant number, since it is smaller than the sum of its proper divisors (110445500).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81060640 is a wasteful number, since it uses less digits than its factorization.

81060640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 506644 (or 506636 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 81060640 is about 9003.3682586019. The cubic root of 81060640 is about 432.7828170158.

Adding to 81060640 its reverse (4606018), we get a palindrome (85666658).

The spelling of 81060640 in words is "eighty-one million, sixty thousand, six hundred forty".