198640896457 has 4 divisors (see below), whose sum is σ = 199035809280. Its totient is φ = 198245983636.

The previous prime is 198640896409. The next prime is 198640896511. The reversal of 198640896457 is 754698046891.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 198640896457 - 2¹¹ = 198640894409 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 198640896392 and 198640896401.

It is not an unprimeable number, because it can be changed into a prime (198640896757) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 197455657 + ... + 197456662.

It is an arithmetic number, because the mean of its divisors is an integer number (49758952320).

Almost surely, 2^198640896457 is an apocalyptic number.

It is an amenable number.

198640896457 is a deficient number, since it is larger than the sum of its proper divisors (394912823).

198640896457 is an equidigital number, since it uses as much as digits as its factorization.

198640896457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 394912822.

The product of its (nonzero) digits is 104509440, while the sum is 67.

The spelling of 198640896457 in words is "one hundred ninety-eight billion, six hundred forty million, eight hundred ninety-six thousand, four hundred fifty-seven".