81621152836 has 24 divisors (see below), whose sum is σ = 143847071424. Its totient is φ = 40522231200.

The previous prime is 81621152827. The next prime is 81621152857. The reversal of 81621152836 is 63825112618.

It is a junction number, because it is equal to n+sod(n) for n = 81621152792 and 81621152801.

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, 1380171 + ... + 1438093.

It is an arithmetic number, because the mean of its divisors is an integer number (5993627976).

Almost surely, 2^81621152836 is an apocalyptic number.

It is an amenable number.

81621152836 is a deficient number, since it is larger than the sum of its proper divisors (62225918588).

81621152836 is a wasteful number, since it uses less digits than its factorization.

81621152836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60411 (or 60409 counting only the distinct ones).

The product of its digits is 138240, while the sum is 43.

The spelling of 81621152836 in words is "eighty-one billion, six hundred twenty-one million, one hundred fifty-two thousand, eight hundred thirty-six".