81399435946 has 16 divisors (see below), whose sum is σ = 122790038400. Its totient is φ = 40469923648.

The previous prime is 81399435937. The next prime is 81399435947. The reversal of 81399435946 is 64953499318.

It is not an unprimeable number, because it can be changed into a prime (81399435947) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 201810 + ... + 451138.

It is an arithmetic number, because the mean of its divisors is an integer number (7674377400).

Almost surely, 2^81399435946 is an apocalyptic number.

81399435946 is a deficient number, since it is larger than the sum of its proper divisors (41390602454).

81399435946 is a wasteful number, since it uses less digits than its factorization.

81399435946 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 250253.

The product of its digits is 25194240, while the sum is 61.

The spelling of 81399435946 in words is "eighty-one billion, three hundred ninety-nine million, four hundred thirty-five thousand, nine hundred forty-six".