2181921375 has 16 divisors (see below), whose sum is σ = 3630717792. Its totient is φ = 1163691200.

The previous prime is 2181921361. The next prime is 2181921431. The reversal of 2181921375 is 5731291812.

It is a happy number.

2181921375 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 2181921375 - 2¹³ = 2181913183 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2908854 + ... + 2909603.

It is an arithmetic number, because the mean of its divisors is an integer number (226919862).

Almost surely, 2^2181921375 is an apocalyptic number.

2181921375 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

2181921375 is a deficient number, since it is larger than the sum of its proper divisors (1448796417).

2181921375 is an equidigital number, since it uses as much as digits as its factorization.

2181921375 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5818475 (or 5818465 counting only the distinct ones).

The product of its digits is 30240, while the sum is 39.

The square root of 2181921375 is about 46711.0412536479. The cubic root of 2181921375 is about 1297.0190821678.

The spelling of 2181921375 in words is "two billion, one hundred eighty-one million, nine hundred twenty-one thousand, three hundred seventy-five".