81252106812 has 18 divisors (see below), whose sum is σ = 205387270088. Its totient is φ = 27084035592.

The previous prime is 81252106783. The next prime is 81252106813. The reversal of 81252106812 is 21860125218.

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×81252106812² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 2257002967 = 81252106812 / (8 + 1 + 2 + 5 + 2 + 1 + 0 + 6 + 8 + 1 + 2).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81252106813) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1128501448 + ... + 1128501519.

Almost surely, 2^81252106812 is an apocalyptic number.

It is an amenable number.

81252106812 is an abundant number, since it is smaller than the sum of its proper divisors (124135163276).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81252106812 is a wasteful number, since it uses less digits than its factorization.

81252106812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2257002977 (or 2257002972 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 36.

The spelling of 81252106812 in words is "eighty-one billion, two hundred fifty-two million, one hundred six thousand, eight hundred twelve".