81707501818 has 16 divisors (see below), whose sum is σ = 125821777536. Its totient is φ = 39771214560.

The previous prime is 81707501803. The next prime is 81707501861. The reversal of 81707501818 is 81810570718.

It is a super-2 number, since 2×81707501818² (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 7 ways as a sum of consecutive naturals, for example, 1038096 + ... + 1114027.

It is an arithmetic number, because the mean of its divisors is an integer number (7863861096).

Almost surely, 2^81707501818 is an apocalyptic number.

81707501818 is a deficient number, since it is larger than the sum of its proper divisors (44114275718).

81707501818 is a wasteful number, since it uses less digits than its factorization.

81707501818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2152629.

The product of its (nonzero) digits is 125440, while the sum is 46.

The spelling of 81707501818 in words is "eighty-one billion, seven hundred seven million, five hundred one thousand, eight hundred eighteen".