19661120816064 has 896 divisors, whose sum is σ = 70199927046144. Its totient is φ = 4707901440000.

The previous prime is 19661120816053. The next prime is 19661120816069. The reversal of 19661120816064 is 46061802116691.

It is a happy number.

It is a hoax number, since the sum of its digits (51) 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 (51).

It is a junction number, because it is equal to n+sod(n) for n = 19661120815998 and 19661120816016.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19661120816069) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 3047760039 + ... + 3047766489.

It is an arithmetic number, because the mean of its divisors is an integer number (78348132864).

Almost surely, 2^{19661120816064} is an apocalyptic number.

19661120816064 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19661120816064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35099963523072).

19661120816064 is an abundant number, since it is smaller than the sum of its proper divisors (50538806230080).

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

19661120816064 is a wasteful number, since it uses less digits than its factorization.

19661120816064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6865 (or 6855 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 51.

The spelling of 19661120816064 in words is "nineteen trillion, six hundred sixty-one billion, one hundred twenty million, eight hundred sixteen thousand, sixty-four".