19497894217 has 8 divisors (see below), whose sum is σ = 19562177480. Its totient is φ = 19433692800.

The previous prime is 19497894209. The next prime is 19497894223. The reversal of 19497894217 is 71249879491.

It can be written as a sum of positive squares in 4 ways, for example, as 1087746361 + 18410147856 = 32981^2 + 135684^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 19497894217 - 2³ = 19497894209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19497894817) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 476467 + ... + 515767.

It is an arithmetic number, because the mean of its divisors is an integer number (2445272185).

Almost surely, 2^19497894217 is an apocalyptic number.

It is an amenable number.

19497894217 is a deficient number, since it is larger than the sum of its proper divisors (64283263).

19497894217 is a wasteful number, since it uses less digits than its factorization.

19497894217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40923.

The product of its digits is 9144576, while the sum is 61.

The spelling of 19497894217 in words is "nineteen billion, four hundred ninety-seven million, eight hundred ninety-four thousand, two hundred seventeen".