81148320252 has 36 divisors (see below), whose sum is σ = 208487629896. Its totient is φ = 26606005920.

The previous prime is 81148320247. The next prime is 81148320263. The reversal of 81148320252 is 25202384118.

It is a happy number.

81148320252 is a `hidden beast` number, since 81 + 1 + 4 + 8 + 320 + 252 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 18474198 + ... + 18478589.

Almost surely, 2^81148320252 is an apocalyptic number.

It is an amenable number.

81148320252 is an abundant number, since it is smaller than the sum of its proper divisors (127339309644).

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

81148320252 is a wasteful number, since it uses less digits than its factorization.

81148320252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36952858 (or 36952853 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 36.

The spelling of 81148320252 in words is "eighty-one billion, one hundred forty-eight million, three hundred twenty thousand, two hundred fifty-two".