81520287773 has 8 divisors (see below), whose sum is σ = 81858815136. Its totient is φ = 81181870000.

The previous prime is 81520287767. The next prime is 81520287781. The reversal of 81520287773 is 37778202518.

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 81520287773 - 2¹⁶ = 81520222237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81520287743) 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, 1683683 + ... + 1731423.

It is an arithmetic number, because the mean of its divisors is an integer number (10232351892).

Almost surely, 2^81520287773 is an apocalyptic number.

It is an amenable number.

81520287773 is a deficient number, since it is larger than the sum of its proper divisors (338527363).

81520287773 is a wasteful number, since it uses less digits than its factorization.

81520287773 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54795.

The product of its (nonzero) digits is 1317120, while the sum is 50.

The spelling of 81520287773 in words is "eighty-one billion, five hundred twenty million, two hundred eighty-seven thousand, seven hundred seventy-three".