81085813740 has 72 divisors (see below), whose sum is σ = 247469350128. Its totient is φ = 21490220160.

The previous prime is 81085813729. The next prime is 81085813763. The reversal of 81085813740 is 4731858018.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (45).

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 23 ways as a sum of consecutive naturals, for example, 1352491 + ... + 1411170.

Almost surely, 2^81085813740 is an apocalyptic number.

It is an amenable number.

81085813740 is an abundant number, since it is smaller than the sum of its proper divisors (166383536388).

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

81085813740 is a wasteful number, since it uses less digits than its factorization.

81085813740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2763839 (or 2763834 counting only the distinct ones).

The product of its (nonzero) digits is 215040, while the sum is 45.

The spelling of 81085813740 in words is "eighty-one billion, eighty-five million, eight hundred thirteen thousand, seven hundred forty".