19640826720 has 72 divisors (see below), whose sum is σ = 67024326096. Its totient is φ = 5237553408.

The previous prime is 19640826703. The next prime is 19640826727. The reversal of 19640826720 is 2762804691.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (72).

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19640826727) 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 11 ways as a sum of consecutive naturals, for example, 6818292 + ... + 6821171.

It is an arithmetic number, because the mean of its divisors is an integer number (930893418).

Almost surely, 2^19640826720 is an apocalyptic number.

19640826720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19640826720 is an abundant number, since it is smaller than the sum of its proper divisors (47383499376).

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

19640826720 is a wasteful number, since it uses less digits than its factorization.

19640826720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13639484 (or 13639473 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The spelling of 19640826720 in words is "nineteen billion, six hundred forty million, eight hundred twenty-six thousand, seven hundred twenty".