81397980121344 has 144 divisors (see below), whose sum is σ = 225245199453120. Its totient is φ = 26064069713920.

The previous prime is 81397980121343. The next prime is 81397980121351. The reversal of 81397980121344 is 44312108979318.

It is not an unprimeable number, because it can be changed into a prime (81397980121343) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4888362 + ... + 13663529.

It is an arithmetic number, because the mean of its divisors is an integer number (1564202773980).

Almost surely, 2^{81397980121344} is an apocalyptic number.

It is an amenable number.

81397980121344 is an abundant number, since it is smaller than the sum of its proper divisors (143847219331776).

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

81397980121344 is a wasteful number, since it uses less digits than its factorization.

81397980121344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18552136 (or 18552122 counting only the distinct ones).

The product of its (nonzero) digits is 10450944, while the sum is 60.

The spelling of 81397980121344 in words is "eighty-one trillion, three hundred ninety-seven billion, nine hundred eighty million, one hundred twenty-one thousand, three hundred forty-four".