1983621544921 has 3 divisors (see below), whose sum is σ = 1983622953333. Its totient is φ = 1983620136510.

The previous prime is 1983621544907. The next prime is 1983621544987. The reversal of 1983621544921 is 1294451263891.

The square root of 1983621544921 is 1408411.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 1983621544921 - 2⁵ = 1983621544889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1983621544991) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 704206 + ... + 2112616.

It is an arithmetic number, because the mean of its divisors is an integer number (661207651111).

Almost surely, 2^{1983621544921} is an apocalyptic number.

1983621544921 is the 1408411-st square number.

1983621544921 is the 704206-th centered octagonal number.

It is an amenable number.

1983621544921 is a deficient number, since it is larger than the sum of its proper divisors (1408412).

1983621544921 is an frugal number, since it uses more digits than its factorization.

1983621544921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2816822 (or 1408411 counting only the distinct ones).

The product of its digits is 3732480, while the sum is 55.

The spelling of 1983621544921 in words is "one trillion, nine hundred eighty-three billion, six hundred twenty-one million, five hundred forty-four thousand, nine hundred twenty-one".