81002886578 has 8 divisors (see below), whose sum is σ = 122707343340. Its totient is φ = 40100438800.

The previous prime is 81002886563. The next prime is 81002886581. The reversal of 81002886578 is 87568820018.

It can be written as a sum of positive squares in 2 ways, for example, as 76786072609 + 4216813969 = 277103^2 + 64937^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×81002886578² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 200501993 + ... + 200502396.

Almost surely, 2^81002886578 is an apocalyptic number.

81002886578 is a deficient number, since it is larger than the sum of its proper divisors (41704456762).

81002886578 is a wasteful number, since it uses less digits than its factorization.

81002886578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 401004492.

The product of its (nonzero) digits is 1720320, while the sum is 53.

The spelling of 81002886578 in words is "eighty-one billion, two million, eight hundred eighty-six thousand, five hundred seventy-eight".