81894723724 has 24 divisors (see below), whose sum is σ = 156355402896. Its totient is φ = 37222272000.

The previous prime is 81894723601. The next prime is 81894723821. The reversal of 81894723724 is 42732749818.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 663004 + ... + 776764.

It is an arithmetic number, because the mean of its divisors is an integer number (6514808454).

Almost surely, 2^81894723724 is an apocalyptic number.

It is an amenable number.

81894723724 is a deficient number, since it is larger than the sum of its proper divisors (74460679172).

81894723724 is a wasteful number, since it uses less digits than its factorization.

81894723724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130137 (or 130135 counting only the distinct ones).

The product of its digits is 5419008, while the sum is 55.

The spelling of 81894723724 in words is "eighty-one billion, eight hundred ninety-four million, seven hundred twenty-three thousand, seven hundred twenty-four".