1791721920 has 224 divisors, whose sum is σ = 5849819136. Its totient is φ = 464486400.

The previous prime is 1791721909. The next prime is 1791721927. The reversal of 1791721920 is 291271971.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1791721927) 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, 6611385 + ... + 6611655.

It is an arithmetic number, because the mean of its divisors is an integer number (26115264).

Almost surely, 2^1791721920 is an apocalyptic number.

1791721920 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 1791721920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2924909568).

1791721920 is an abundant number, since it is smaller than the sum of its proper divisors (4058097216).

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

1791721920 is a wasteful number, since it uses less digits than its factorization.

1791721920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 459 (or 449 counting only the distinct ones).

The product of its (nonzero) digits is 15876, while the sum is 39.

The square root of 1791721920 is about 42328.7363383317. The cubic root of 1791721920 is about 1214.5727570283.

The spelling of 1791721920 in words is "one billion, seven hundred ninety-one million, seven hundred twenty-one thousand, nine hundred twenty".