19801617620400 has 3840 divisors, whose sum is σ = 93355396300800. Its totient is φ = 3901080268800.

The previous prime is 19801617620399. The next prime is 19801617620429. The reversal of 19801617620400 is 402671610891.

19801617620400 is a `hidden beast` number, since 1 + 9 + 8 + 0 + 1 + 6 + 17 + 620 + 4 + 0 + 0 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 767 ways as a sum of consecutive naturals, for example, 250653387561 + ... + 250653387639.

It is an arithmetic number, because the mean of its divisors is an integer number (24311301120).

Almost surely, 2^{19801617620400} is an apocalyptic number.

19801617620400 is a gapful number since it is divisible by the number (10) 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 19801617620400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46677698150400).

19801617620400 is an abundant number, since it is smaller than the sum of its proper divisors (73553778680400).

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

19801617620400 is a wasteful number, since it uses less digits than its factorization.

19801617620400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 246 (or 207 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The spelling of 19801617620400 in words is "nineteen trillion, eight hundred one billion, six hundred seventeen million, six hundred twenty thousand, four hundred".