81387085390 has 96 divisors (see below), whose sum is σ = 173747923776. Its totient is φ = 27230860800.

The previous prime is 81387085303. The next prime is 81387085397. The reversal of 81387085390 is 9358078318.

It is a super-5 number, since 5×81387085390⁵ (a number of 56 digits) contains 55555 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81387085397) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 1041690 + ... + 1117090.

It is an arithmetic number, because the mean of its divisors is an integer number (1809874206).

Almost surely, 2^81387085390 is an apocalyptic number.

81387085390 is an abundant number, since it is smaller than the sum of its proper divisors (92360838386).

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

81387085390 is a wasteful number, since it uses less digits than its factorization.

81387085390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75482 (or 75463 counting only the distinct ones).

The product of its (nonzero) digits is 1451520, while the sum is 52.

The spelling of 81387085390 in words is "eighty-one billion, three hundred eighty-seven million, eighty-five thousand, three hundred ninety".