81551193015 has 16 divisors (see below), whose sum is σ = 132943832928. Its totient is φ = 42673328256.

The previous prime is 81551193001. The next prime is 81551193041. The reversal of 81551193015 is 51039115518.

It is not a de Polignac number, because 81551193015 - 2⁶ = 81551192951 is a prime.

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, 51289264 + ... + 51290853.

It is an arithmetic number, because the mean of its divisors is an integer number (8308989558).

Almost surely, 2^81551193015 is an apocalyptic number.

81551193015 is a deficient number, since it is larger than the sum of its proper divisors (51392639913).

81551193015 is a wasteful number, since it uses less digits than its factorization.

81551193015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102580178.

The product of its (nonzero) digits is 27000, while the sum is 39.

The spelling of 81551193015 in words is "eighty-one billion, five hundred fifty-one million, one hundred ninety-three thousand, fifteen".