81507403850 has 12 divisors (see below), whose sum is σ = 151603771254. Its totient is φ = 32602961520.

The previous prime is 81507403837. The next prime is 81507403871. The reversal of 81507403850 is 5830470518.

It can be written as a sum of positive squares in 3 ways, for example, as 31531460041 + 49975943809 = 177571^2 + 223553^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81507403798 and 81507403807.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 815073989 + ... + 815074088.

Almost surely, 2^81507403850 is an apocalyptic number.

81507403850 is a deficient number, since it is larger than the sum of its proper divisors (70096367404).

81507403850 is a wasteful number, since it uses less digits than its factorization.

81507403850 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1630148089 (or 1630148084 counting only the distinct ones).

The product of its (nonzero) digits is 134400, while the sum is 41.

The spelling of 81507403850 in words is "eighty-one billion, five hundred seven million, four hundred three thousand, eight hundred fifty".