1621899256320 has 480 divisors, whose sum is σ = 6435124375680. Its totient is φ = 369819648000.

The previous prime is 1621899256303. The next prime is 1621899256343. The reversal of 1621899256320 is 236529981261.

1621899256320 is a `hidden beast` number, since 1 + 6 + 2 + 189 + 92 + 56 + 320 = 666.

It is a tau number, because it is divible by the number of its divisors (480).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 67564320 + ... + 67588320.

It is an arithmetic number, because the mean of its divisors is an integer number (13406509116).

Almost surely, 2^{1621899256320} is an apocalyptic number.

1621899256320 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 1621899256320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3217562187840).

1621899256320 is an abundant number, since it is smaller than the sum of its proper divisors (4813225119360).

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

1621899256320 is a wasteful number, since it uses less digits than its factorization.

1621899256320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24456 (or 24437 counting only the distinct ones).

The product of its (nonzero) digits is 2799360, while the sum is 54.

The spelling of 1621899256320 in words is "one trillion, six hundred twenty-one billion, eight hundred ninety-nine million, two hundred fifty-six thousand, three hundred twenty".