1821721752 has 40 divisors (see below), whose sum is σ = 5102509500. Its totient is φ = 607240368.

The previous prime is 1821721679. The next prime is 1821721817. The reversal of 1821721752 is 2571271281.

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

It is a congruent number.

It is an unprimeable number.

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 9 ways as a sum of consecutive naturals, for example, 1405002 + ... + 1406297.

Almost surely, 2^1821721752 is an apocalyptic number.

1821721752 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1821721752 is an abundant number, since it is smaller than the sum of its proper divisors (3280787748).

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

1821721752 is a wasteful number, since it uses less digits than its factorization.

1821721752 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2811317 (or 2811304 counting only the distinct ones).

The product of its digits is 15680, while the sum is 36.

The square root of 1821721752 is about 42681.6324898662. The cubic root of 1821721752 is about 1221.3140352170.

The spelling of 1821721752 in words is "one billion, eight hundred twenty-one million, seven hundred twenty-one thousand, seven hundred fifty-two".