81206740 has 12 divisors (see below), whose sum is σ = 170534196. Its totient is φ = 32482688.

The previous prime is 81206737. The next prime is 81206771. The reversal of 81206740 is 4760218.

It can be written as a sum of positive squares in 2 ways, for example, as 11751184 + 69455556 = 3428^2 + 8334^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81206699 and 81206708.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2030149 + ... + 2030188.

It is an arithmetic number, because the mean of its divisors is an integer number (14211183).

Almost surely, 2^81206740 is an apocalyptic number.

It is an amenable number.

81206740 is an abundant number, since it is smaller than the sum of its proper divisors (89327456).

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

81206740 is a wasteful number, since it uses less digits than its factorization.

81206740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4060346 (or 4060344 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 81206740 is about 9011.4782361164. The cubic root of 81206740 is about 433.0426702985.

Adding to 81206740 its reverse (4760218), we get a palindrome (85966958).

The spelling of 81206740 in words is "eighty-one million, two hundred six thousand, seven hundred forty".