19664517 has 12 divisors (see below), whose sum is σ = 27411104. Its totient is φ = 12538680.

The previous prime is 19664503. The next prime is 19664527. The reversal of 19664517 is 71546691.

It is not a de Polignac number, because 19664517 - 2⁶ = 19664453 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19664527) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4609 + ... + 7782.

Almost surely, 2^19664517 is an apocalyptic number.

It is an amenable number.

19664517 is a deficient number, since it is larger than the sum of its proper divisors (7746587).

19664517 is a wasteful number, since it uses less digits than its factorization.

19664517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12440 (or 12417 counting only the distinct ones).

The product of its digits is 45360, while the sum is 39.

The square root of 19664517 is about 4434.4691903316. The cubic root of 19664517 is about 269.9154605011.

The spelling of 19664517 in words is "nineteen million, six hundred sixty-four thousand, five hundred seventeen".