19401617664 has 504 divisors, whose sum is σ = 68309596992. Its totient is φ = 5419560960.

The previous prime is 19401617647. The next prime is 19401617681. The reversal of 19401617664 is 46671610491.

19401617664 is a `hidden beast` number, since 19 + 401 + 6 + 176 + 64 = 666.

It is an interprime number because it is at equal distance from previous prime (19401617647) and next prime (19401617681).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 26686869 + ... + 26687595.

Almost surely, 2^19401617664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19401617664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34154798496).

19401617664 is an abundant number, since it is smaller than the sum of its proper divisors (48907979328).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19401617664 is an equidigital number, since it uses as much as digits as its factorization.

19401617664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 785 (or 756 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

The spelling of 19401617664 in words is "nineteen billion, four hundred one million, six hundred seventeen thousand, six hundred sixty-four".