81166644627951 has 8 divisors (see below), whose sum is σ = 113918097723520. Its totient is φ = 51263143975512.

The previous prime is 81166644627919. The next prime is 81166644627983. The reversal of 81166644627951 is 15972644666118.

It is an interprime number because it is at equal distance from previous prime (81166644627919) and next prime (81166644627983).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81166644627951 - 2⁵ = 81166644627919 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81166644627251) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 711988110715 + ... + 711988110828.

It is an arithmetic number, because the mean of its divisors is an integer number (14239762215440).

Almost surely, 2^{81166644627951} is an apocalyptic number.

81166644627951 is a deficient number, since it is larger than the sum of its proper divisors (32751453095569).

81166644627951 is a wasteful number, since it uses less digits than its factorization.

81166644627951 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1423976221565.

The product of its digits is 104509440, while the sum is 66.

The spelling of 81166644627951 in words is "eighty-one trillion, one hundred sixty-six billion, six hundred forty-four million, six hundred twenty-seven thousand, nine hundred fifty-one".