1981421395200 has 1728 divisors, whose sum is σ = 8306057267200. Its totient is φ = 458647142400.

The previous prime is 1981421395123. The next prime is 1981421395249. The reversal of 1981421395200 is 25931241891.

1981421395200 is a `hidden beast` number, since 1 + 9 + 81 + 42 + 1 + 3 + 9 + 520 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1728).

It is a super-3 number, since 3×1981421395200³ (a number of 38 digits) contains 333 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 2576620416 + ... + 2576621184.

Almost surely, 2^{1981421395200} is an apocalyptic number.

1981421395200 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 1981421395200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4153028633600).

1981421395200 is an abundant number, since it is smaller than the sum of its proper divisors (6324635872000).

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

1981421395200 is a wasteful number, since it uses less digits than its factorization.

1981421395200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 885 (or 860 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The spelling of 1981421395200 in words is "one trillion, nine hundred eighty-one billion, four hundred twenty-one million, three hundred ninety-five thousand, two hundred".