81394787642 has 8 divisors (see below), whose sum is σ = 139533921696. Its totient is φ = 34883480412.

The previous prime is 81394787623. The next prime is 81394787651. The reversal of 81394787642 is 24678749318.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×81394787642² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2906956688 + ... + 2906956715.

It is an arithmetic number, because the mean of its divisors is an integer number (17441740212).

Almost surely, 2^81394787642 is an apocalyptic number.

81394787642 is a deficient number, since it is larger than the sum of its proper divisors (58139134054).

81394787642 is a wasteful number, since it uses less digits than its factorization.

81394787642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5813913412.

The product of its digits is 16257024, while the sum is 59.

The spelling of 81394787642 in words is "eighty-one billion, three hundred ninety-four million, seven hundred eighty-seven thousand, six hundred forty-two".