81343510772 has 6 divisors (see below), whose sum is σ = 142351143858. Its totient is φ = 40671755384.

The previous prime is 81343510757. The next prime is 81343510793. The reversal of 81343510772 is 27701534318.

It can be written as a sum of positive squares in only one way, i.e., 70966828816 + 10376681956 = 266396^2 + 101866^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10167938843 + ... + 10167938850.

It is an arithmetic number, because the mean of its divisors is an integer number (23725190643).

Almost surely, 2^81343510772 is an apocalyptic number.

It is an amenable number.

81343510772 is a deficient number, since it is larger than the sum of its proper divisors (61007633086).

81343510772 is a wasteful number, since it uses less digits than its factorization.

81343510772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20335877697 (or 20335877695 counting only the distinct ones).

The product of its (nonzero) digits is 141120, while the sum is 41.

The spelling of 81343510772 in words is "eighty-one billion, three hundred forty-three million, five hundred ten thousand, seven hundred seventy-two".