81007850781 has 96 divisors (see below), whose sum is σ = 145712286720. Its totient is φ = 42606950400.

The previous prime is 81007850779. The next prime is 81007850813. The reversal of 81007850781 is 18705870018.

It is not a de Polignac number, because 81007850781 - 2¹ = 81007850779 is a prime.

It is a super-2 number, since 2×81007850781² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81007850761) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 31263796 + ... + 31266386.

It is an arithmetic number, because the mean of its divisors is an integer number (1517836320).

Almost surely, 2^81007850781 is an apocalyptic number.

It is an amenable number.

81007850781 is a deficient number, since it is larger than the sum of its proper divisors (64704435939).

81007850781 is a wasteful number, since it uses less digits than its factorization.

81007850781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4067 (or 4064 counting only the distinct ones).

The product of its (nonzero) digits is 125440, while the sum is 45.

The spelling of 81007850781 in words is "eighty-one billion, seven million, eight hundred fifty thousand, seven hundred eighty-one".