81765488100 has 36 divisors (see below), whose sum is σ = 236574813104. Its totient is φ = 21804130080.

The previous prime is 81765488089. The next prime is 81765488131. The reversal of 81765488100 is 188456718.

It is a happy number.

It is a super-2 number, since 2×81765488100² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81765488100.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 136275514 + ... + 136276113.

Almost surely, 2^81765488100 is an apocalyptic number.

It is an amenable number.

81765488100 is an abundant number, since it is smaller than the sum of its proper divisors (154809325004).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81765488100 is a wasteful number, since it uses less digits than its factorization.

81765488100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 272551644 (or 272551637 counting only the distinct ones).

The product of its (nonzero) digits is 430080, while the sum is 48.

The spelling of 81765488100 in words is "eighty-one billion, seven hundred sixty-five million, four hundred eighty-eight thousand, one hundred".