81368805 has 48 divisors (see below), whose sum is σ = 152836992. Its totient is φ = 36211200.

The previous prime is 81368803. The next prime is 81368813. The reversal of 81368805 is 50886318.

It is a happy number.

It is not a de Polignac number, because 81368805 - 2¹ = 81368803 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81368803) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 176275 + ... + 176735.

It is an arithmetic number, because the mean of its divisors is an integer number (3184104).

Almost surely, 2^81368805 is an apocalyptic number.

It is an amenable number.

81368805 is a deficient number, since it is larger than the sum of its proper divisors (71468187).

81368805 is a wasteful number, since it uses less digits than its factorization.

81368805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 558 (or 517 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 39.

The square root of 81368805 is about 9020.4658970588. The cubic root of 81368805 is about 433.3305545515.

The spelling of 81368805 in words is "eighty-one million, three hundred sixty-eight thousand, eight hundred five".