81202641591 has 8 divisors (see below), whose sum is σ = 108445102720. Its totient is φ = 54047637432.

The previous prime is 81202641547. The next prime is 81202641607. The reversal of 81202641591 is 19514620218.

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

It is not a de Polignac number, because 81202641591 - 2¹¹ = 81202639543 is a prime.

It is a super-2 number, since 2×81202641591² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81202641691) 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, 21862075 + ... + 21865788.

It is an arithmetic number, because the mean of its divisors is an integer number (13555637840).

Almost surely, 2^81202641591 is an apocalyptic number.

81202641591 is a deficient number, since it is larger than the sum of its proper divisors (27242461129).

81202641591 is a wasteful number, since it uses less digits than its factorization.

81202641591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43728485.

The product of its (nonzero) digits is 34560, while the sum is 39.

The spelling of 81202641591 in words is "eighty-one billion, two hundred two million, six hundred forty-one thousand, five hundred ninety-one".