81708747194 has 4 divisors (see below), whose sum is σ = 122563120794. Its totient is φ = 40854373596.

The previous prime is 81708747191. The next prime is 81708747223. The reversal of 81708747194 is 49174780718.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 72870303025 + 8838444169 = 269945^2 + 94013^2 .

It is not an unprimeable number, because it can be changed into a prime (81708747191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20427186797 + ... + 20427186800.

Almost surely, 2^81708747194 is an apocalyptic number.

81708747194 is a deficient number, since it is larger than the sum of its proper divisors (40854373600).

81708747194 is a wasteful number, since it uses less digits than its factorization.

81708747194 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40854373599.

The product of its (nonzero) digits is 3161088, while the sum is 56.

The spelling of 81708747194 in words is "eighty-one billion, seven hundred eight million, seven hundred forty-seven thousand, one hundred ninety-four".