81597269376 has 384 divisors, whose sum is σ = 287905363200. Its totient is φ = 22507849728.

The previous prime is 81597269363. The next prime is 81597269387. The reversal of 81597269376 is 67396279518.

81597269376 is a `hidden beast` number, since 8 + 1 + 597 + 2 + 6 + 9 + 37 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a super-2 number, since 2×81597269376² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6307651 + ... + 6320573.

It is an arithmetic number, because the mean of its divisors is an integer number (749753550).

Almost surely, 2^81597269376 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81597269376, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (143952681600).

81597269376 is an abundant number, since it is smaller than the sum of its proper divisors (206308093824).

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

81597269376 is a wasteful number, since it uses less digits than its factorization.

81597269376 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12988 (or 12964 counting only the distinct ones).

The product of its digits is 34292160, while the sum is 63.

The spelling of 81597269376 in words is "eighty-one billion, five hundred ninety-seven million, two hundred sixty-nine thousand, three hundred seventy-six".