19945677680 has 20 divisors (see below), whose sum is σ = 46373700792. Its totient is φ = 7978271040.

The previous prime is 19945677659. The next prime is 19945677683. The reversal of 19945677680 is 8677654991.

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×19945677680² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19945677683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 124660406 + ... + 124660565.

Almost surely, 2^19945677680 is an apocalyptic number.

19945677680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19945677680 is an abundant number, since it is smaller than the sum of its proper divisors (26428023112).

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

19945677680 is a wasteful number, since it uses less digits than its factorization.

19945677680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 249320984 (or 249320978 counting only the distinct ones).

The product of its (nonzero) digits is 22861440, while the sum is 62.

The spelling of 19945677680 in words is "nineteen billion, nine hundred forty-five million, six hundred seventy-seven thousand, six hundred eighty".