1621831680 has 416 divisors, whose sum is σ = 6605222400. Its totient is φ = 369819648.

The previous prime is 1621831669. The next prime is 1621831721. The reversal of 1621831680 is 861381261.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3870511 + ... + 3870929.

Almost surely, 2^1621831680 is an apocalyptic number.

1621831680 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 1621831680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3302611200).

1621831680 is an abundant number, since it is smaller than the sum of its proper divisors (4983390720).

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

1621831680 is an equidigital number, since it uses as much as digits as its factorization.

1621831680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 464 (or 436 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 1621831680 is about 40271.9713945071. The cubic root of 1621831680 is about 1174.9027666635.

The spelling of 1621831680 in words is "one billion, six hundred twenty-one million, eight hundred thirty-one thousand, six hundred eighty".