81679353616 has 135 divisors (see below), whose sum is σ = 188352875541. Its totient is φ = 34213210752.

The previous prime is 81679353583. The next prime is 81679353647. The reversal of 81679353616 is 61635397618.

The square root of 81679353616 is 285796.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 74299856400 + 7379497216 = 272580^2 + 85904^2 .

It is a super-3 number, since 3×81679353616³ (a number of 34 digits) contains 333 as substring.

It is a Duffinian number.

Its product of digits (4898880) is a multiple of the sum of its prime factors (486).

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 472134906 + ... + 472135078.

Almost surely, 2^81679353616 is an apocalyptic number.

81679353616 is the 285796-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81679353616

81679353616 is an abundant number, since it is smaller than the sum of its proper divisors (106673521925).

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

81679353616 is an equidigital number, since it uses as much as digits as its factorization.

81679353616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 486 (or 241 counting only the distinct ones).

The product of its digits is 4898880, while the sum is 55.

The spelling of 81679353616 in words is "eighty-one billion, six hundred seventy-nine million, three hundred fifty-three thousand, six hundred sixteen".