851897491617 has 16 divisors (see below), whose sum is σ = 1175161366080. Its totient is φ = 548286984000.

The previous prime is 851897491609. The next prime is 851897491619. The reversal of 851897491617 is 716194798158.

It is not a de Polignac number, because 851897491617 - 2³ = 851897491609 is a prime.

It is not an unprimeable number, because it can be changed into a prime (851897491619) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 252367 + ... + 1329467.

It is an arithmetic number, because the mean of its divisors is an integer number (73447585380).

Almost surely, 2^851897491617 is an apocalyptic number.

851897491617 is a gapful number since it is divisible by the number (87) formed by its first and last digit.

It is an amenable number.

851897491617 is a deficient number, since it is larger than the sum of its proper divisors (323263874463).

851897491617 is a wasteful number, since it uses less digits than its factorization.

851897491617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1086224.

The product of its digits is 30481920, while the sum is 66.

The spelling of 851897491617 in words is "eight hundred fifty-one billion, eight hundred ninety-seven million, four hundred ninety-one thousand, six hundred seventeen".