81501324977 has 8 divisors (see below), whose sum is σ = 81782656200. Its totient is φ = 81220423680.

The previous prime is 81501324973. The next prime is 81501324991. The reversal of 81501324977 is 77942310518.

It can be written as a sum of positive squares in 4 ways, for example, as 157151296 + 81344173681 = 12536^2 + 285209^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 81501324977 - 2² = 81501324973 is a prime.

It is a super-3 number, since 3×81501324977³ (a number of 34 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81501324973) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 274649 + ... + 488297.

It is an arithmetic number, because the mean of its divisors is an integer number (10222832025).

Almost surely, 2^81501324977 is an apocalyptic number.

It is an amenable number.

81501324977 is a deficient number, since it is larger than the sum of its proper divisors (281331223).

81501324977 is a wasteful number, since it uses less digits than its factorization.

81501324977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214963.

The product of its (nonzero) digits is 423360, while the sum is 47.

The spelling of 81501324977 in words is "eighty-one billion, five hundred one million, three hundred twenty-four thousand, nine hundred seventy-seven".