1620221000 has 64 divisors (see below), whose sum is σ = 3853614960. Its totient is φ = 637440000.

The previous prime is 1620220999. The next prime is 1620221011. The reversal of 1620221000 is 1220261.

It can be written as a sum of positive squares in 8 ways, for example, as 10125124 + 1610095876 = 3182^2 + 40126^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47720 + ... + 74280.

Almost surely, 2^1620221000 is an apocalyptic number.

1620221000 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 1620221000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1926807480).

1620221000 is an abundant number, since it is smaller than the sum of its proper divisors (2233393960).

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

1620221000 is a wasteful number, since it uses less digits than its factorization.

1620221000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26643 (or 26629 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 1620221000 is about 40251.9688959435. The cubic root of 1620221000 is about 1174.5136964500.

Adding to 1620221000 its reverse (1220261), we get a palindrome (1621441261).

The spelling of 1620221000 in words is "one billion, six hundred twenty million, two hundred twenty-one thousand".