81975154462656 has 2688 divisors, whose sum is σ = 315782303907840. Its totient is φ = 18193003315200.

The previous prime is 81975154462573. The next prime is 81975154462679. The reversal of 81975154462656 is 65626445157918.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 127886356096 + ... + 127886356736.

It is an arithmetic number, because the mean of its divisors is an integer number (117478535680).

Almost surely, 2^{81975154462656} is an apocalyptic number.

81975154462656 is a gapful number since it is divisible by the number (86) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81975154462656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (157891151953920).

81975154462656 is an abundant number, since it is smaller than the sum of its proper divisors (233807149445184).

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

81975154462656 is a wasteful number, since it uses less digits than its factorization.

81975154462656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 803 (or 776 counting only the distinct ones).

The product of its digits is 435456000, while the sum is 69.

The spelling of 81975154462656 in words is "eighty-one trillion, nine hundred seventy-five billion, one hundred fifty-four million, four hundred sixty-two thousand, six hundred fifty-six".