81735261738 has 48 divisors (see below), whose sum is σ = 177361345440. Its totient is φ = 25099743552.

The previous prime is 81735261691. The next prime is 81735261749. The reversal of 81735261738 is 83716253718.

It is a super-2 number, since 2×81735261738² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 436945 + ... + 595307.

It is an arithmetic number, because the mean of its divisors is an integer number (3695028030).

Almost surely, 2^81735261738 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81735261738, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88680672720).

81735261738 is an abundant number, since it is smaller than the sum of its proper divisors (95626083702).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81735261738 is a wasteful number, since it uses less digits than its factorization.

81735261738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158903 (or 158890 counting only the distinct ones).

The product of its digits is 1693440, while the sum is 51.

The spelling of 81735261738 in words is "eighty-one billion, seven hundred thirty-five million, two hundred sixty-one thousand, seven hundred thirty-eight".