1641947220 has 96 divisors (see below), whose sum is σ = 5142816000. Its totient is φ = 434892672.

The previous prime is 1641947191. The next prime is 1641947221. The reversal of 1641947220 is 227491461.

It is a happy number.

1641947220 is a `hidden beast` number, since 1 + 641 + 9 + 4 + 7 + 2 + 2 + 0 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1641947221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 70257 + ... + 90663.

It is an arithmetic number, because the mean of its divisors is an integer number (53571000).

Almost surely, 2^1641947220 is an apocalyptic number.

1641947220 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 1641947220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2571408000).

1641947220 is an abundant number, since it is smaller than the sum of its proper divisors (3500868780).

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

1641947220 is a wasteful number, since it uses less digits than its factorization.

1641947220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20574 (or 20566 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 1641947220 is about 40520.9479158620. The cubic root of 1641947220 is about 1179.7402521252.

The spelling of 1641947220 in words is "one billion, six hundred forty-one million, nine hundred forty-seven thousand, two hundred twenty".