81855691502 has 32 divisors (see below), whose sum is σ = 134435499744. Its totient is φ = 37149321600.

The previous prime is 81855691481. The next prime is 81855691559. The reversal of 81855691502 is 20519655818.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8237477 + ... + 8247407.

It is an arithmetic number, because the mean of its divisors is an integer number (4201109367).

Almost surely, 2^81855691502 is an apocalyptic number.

81855691502 is a deficient number, since it is larger than the sum of its proper divisors (52579808242).

81855691502 is a wasteful number, since it uses less digits than its factorization.

81855691502 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15204.

The product of its (nonzero) digits is 864000, while the sum is 50.

The spelling of 81855691502 in words is "eighty-one billion, eight hundred fifty-five million, six hundred ninety-one thousand, five hundred two".