81361337800 has 48 divisors (see below), whose sum is σ = 191038079700. Its totient is φ = 32222304000.

The previous prime is 81361337789. The next prime is 81361337821. The reversal of 81361337800 is 873316318.

It can be written as a sum of positive squares in 6 ways, for example, as 48532971204 + 32828366596 = 220302^2 + 181186^2 .

It is a Harshad number since it is a multiple of its sum of digits (40).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1993695 + ... + 2034094.

Almost surely, 2^81361337800 is an apocalyptic number.

It is an amenable number.

81361337800 is an abundant number, since it is smaller than the sum of its proper divisors (109676741900).

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

81361337800 is a wasteful number, since it uses less digits than its factorization.

81361337800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4027906 (or 4027897 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 40.

The spelling of 81361337800 in words is "eighty-one billion, three hundred sixty-one million, three hundred thirty-seven thousand, eight hundred".