81144915501 has 24 divisors (see below), whose sum is σ = 117247666656. Its totient is φ = 49896250560.

The previous prime is 81144915487. The next prime is 81144915503. The reversal of 81144915501 is 10551944118.

It is not a de Polignac number, because 81144915501 - 2¹⁷ = 81144784429 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81144915501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81144915503) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 592551 + ... + 716523.

It is an arithmetic number, because the mean of its divisors is an integer number (4885319444).

Almost surely, 2^81144915501 is an apocalyptic number.

It is an amenable number.

81144915501 is a deficient number, since it is larger than the sum of its proper divisors (36102751155).

81144915501 is a wasteful number, since it uses less digits than its factorization.

81144915501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125293 (or 125280 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 39.

The spelling of 81144915501 in words is "eighty-one billion, one hundred forty-four million, nine hundred fifteen thousand, five hundred one".