81894941951724 has 576 divisors, whose sum is σ = 250745554160640. Its totient is φ = 22840102656000.

The previous prime is 81894941951671. The next prime is 81894941951743. The reversal of 81894941951724 is 42715914949818.

81894941951724 is a `hidden beast` number, since 8 + 1 + 8 + 9 + 4 + 94 + 19 + 517 + 2 + 4 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 23127629394 + ... + 23127632934.

It is an arithmetic number, because the mean of its divisors is an integer number (435322142640).

Almost surely, 2^{81894941951724} 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 81894941951724, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125372777080320).

81894941951724 is an abundant number, since it is smaller than the sum of its proper divisors (168850612208916).

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

81894941951724 is a wasteful number, since it uses less digits than its factorization.

81894941951724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3907 (or 3772 counting only the distinct ones).

The product of its digits is 209018880, while the sum is 72.

The spelling of 81894941951724 in words is "eighty-one trillion, eight hundred ninety-four billion, nine hundred forty-one million, nine hundred fifty-one thousand, seven hundred twenty-four".