81394557802 has 8 divisors (see below), whose sum is σ = 122093295876. Its totient is φ = 40696792512.

The previous prime is 81394557779. The next prime is 81394557817. The reversal of 81394557802 is 20875549318.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 81288282321 + 106275481 = 285111^2 + 10309^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 81394557802.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25248 + ... + 404260.

Almost surely, 2^81394557802 is an apocalyptic number.

81394557802 is a deficient number, since it is larger than the sum of its proper divisors (40698738074).

81394557802 is a wasteful number, since it uses less digits than its factorization.

81394557802 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 486392.

The product of its (nonzero) digits is 2419200, while the sum is 52.

The spelling of 81394557802 in words is "eighty-one billion, three hundred ninety-four million, five hundred fifty-seven thousand, eight hundred two".