1621885440 has 160 divisors (see below), whose sum is σ = 5925870720. Its totient is φ = 370704384.

The previous prime is 1621885423. The next prime is 1621885501. The reversal of 1621885440 is 445881261.

It is a tau number, because it is divible by the number of its divisors (160).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38676 + ... + 68844.

It is an arithmetic number, because the mean of its divisors is an integer number (37036692).

Almost surely, 2^1621885440 is an apocalyptic number.

1621885440 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 1621885440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2962935360).

1621885440 is an abundant number, since it is smaller than the sum of its proper divisors (4303985280).

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

1621885440 is an equidigital number, since it uses as much as digits as its factorization.

1621885440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30202 (or 30186 counting only the distinct ones).

The product of its (nonzero) digits is 61440, while the sum is 39.

The square root of 1621885440 is about 40272.6388507135. The cubic root of 1621885440 is about 1174.9157482973.

The spelling of 1621885440 in words is "one billion, six hundred twenty-one million, eight hundred eighty-five thousand, four hundred forty".