81215305700 has 18 divisors (see below), whose sum is σ = 176237213586. Its totient is φ = 32486122240.

The previous prime is 81215305663. The next prime is 81215305711. The reversal of 81215305700 is 750351218.

It can be written as a sum of positive squares in 3 ways, for example, as 9684544 + 81205621156 = 3112^2 + 284966^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 406076429 + ... + 406076628.

Almost surely, 2^81215305700 is an apocalyptic number.

It is an amenable number.

81215305700 is an abundant number, since it is smaller than the sum of its proper divisors (95021907886).

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

81215305700 is a wasteful number, since it uses less digits than its factorization.

81215305700 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 812153071 (or 812153064 counting only the distinct ones).

The product of its (nonzero) digits is 8400, while the sum is 32.

Adding to 81215305700 its reverse (750351218), we get a palindrome (81965656918).

The spelling of 81215305700 in words is "eighty-one billion, two hundred fifteen million, three hundred five thousand, seven hundred".