81042059493 has 10 divisors (see below), whose sum is σ = 121062829734. Its totient is φ = 54028039608.

The previous prime is 81042059489. The next prime is 81042059509. The reversal of 81042059493 is 39495024018.

81042059493 is a `hidden beast` number, since 8 + 10 + 42 + 0 + 594 + 9 + 3 = 666.

It can be written as a sum of positive squares in only one way, i.e., 74743732449 + 6298327044 = 273393^2 + 79362^2 .

It is not a de Polignac number, because 81042059493 - 2² = 81042059489 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81042059443) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 500259546 + ... + 500259707.

Almost surely, 2^81042059493 is an apocalyptic number.

It is an amenable number.

81042059493 is a deficient number, since it is larger than the sum of its proper divisors (40020770241).

81042059493 is a wasteful number, since it uses less digits than its factorization.

81042059493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1000519265 (or 1000519256 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The spelling of 81042059493 in words is "eighty-one billion, forty-two million, fifty-nine thousand, four hundred ninety-three".