2155921920 has 400 divisors, whose sum is σ = 7958751768. Its totient is φ = 557383680.

The previous prime is 2155921919. The next prime is 2155921949. The reversal of 2155921920 is 291295512.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 2110116096 + 45805824 = 45936^2 + 6768^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 7672180 + ... + 7672460.

Almost surely, 2^2155921920 is an apocalyptic number.

2155921920 is a gapful number since it is divisible by the number (20) 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 2155921920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3979375884).

2155921920 is an abundant number, since it is smaller than the sum of its proper divisors (5802829848).

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

2155921920 is an equidigital number, since it uses as much as digits as its factorization.

2155921920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 353 (or 328 counting only the distinct ones).

The product of its (nonzero) digits is 16200, while the sum is 36.

The square root of 2155921920 is about 46431.9062714423. The cubic root of 2155921920 is about 1291.8467869707.

The spelling of 2155921920 in words is "two billion, one hundred fifty-five million, nine hundred twenty-one thousand, nine hundred twenty".