81538347162578 has 16 divisors (see below), whose sum is σ = 124892749330200. Its totient is φ = 39910857133056.

The previous prime is 81538347162511. The next prime is 81538347162583. The reversal of 81538347162578 is 87526174383518.

It can be written as a sum of positive squares in 4 ways, for example, as 79279737942889 + 2258609219689 = 8903917^2 + 1502867^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 856555625 + ... + 856650812.

Almost surely, 2^{81538347162578} is an apocalyptic number.

81538347162578 is a deficient number, since it is larger than the sum of its proper divisors (43354402167622).

81538347162578 is a wasteful number, since it uses less digits than its factorization.

81538347162578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1713206941.

The product of its digits is 270950400, while the sum is 68.

The spelling of 81538347162578 in words is "eighty-one trillion, five hundred thirty-eight billion, three hundred forty-seven million, one hundred sixty-two thousand, five hundred seventy-eight".