1620891648 has 144 divisors (see below), whose sum is σ = 4856309640. Its totient is φ = 540131328.

The previous prime is 1620891611. The next prime is 1620891683. The reversal of 1620891648 is 8461980261.

1620891648 is a `hidden beast` number, since 1 + 620 + 8 + 9 + 16 + 4 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 496036 + ... + 499292.

Almost surely, 2^1620891648 is an apocalyptic number.

1620891648 is a gapful number since it is divisible by the number (18) 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 1620891648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2428154820).

1620891648 is an abundant number, since it is smaller than the sum of its proper divisors (3235417992).

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

1620891648 is an frugal number, since it uses more digits than its factorization.

1620891648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3294 (or 3262 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 45.

The square root of 1620891648 is about 40260.2986576106. The cubic root of 1620891648 is about 1174.6757271454.

The spelling of 1620891648 in words is "one billion, six hundred twenty million, eight hundred ninety-one thousand, six hundred forty-eight".