81698185306 has 8 divisors (see below), whose sum is σ = 125536236084. Its totient is φ = 39852773280.

The previous prime is 81698185277. The next prime is 81698185307. The reversal of 81698185306 is 60358189618.

It can be written as a sum of positive squares in 2 ways, for example, as 81601064281 + 97121025 = 285659^2 + 9855^2 .

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

It is not an unprimeable number, because it can be changed into a prime (81698185307) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 498159585 + ... + 498159748.

Almost surely, 2^81698185306 is an apocalyptic number.

81698185306 is a deficient number, since it is larger than the sum of its proper divisors (43838050778).

81698185306 is a wasteful number, since it uses less digits than its factorization.

81698185306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 996319376.

The product of its (nonzero) digits is 2488320, while the sum is 55.

The spelling of 81698185306 in words is "eighty-one billion, six hundred ninety-eight million, one hundred eighty-five thousand, three hundred six".