1819960921 has 9 divisors (see below), whose sum is σ = 1872102141. Its totient is φ = 1769236992.

The previous prime is 1819960907. The next prime is 1819960943. The reversal of 1819960921 is 1290699181.

The square root of 1819960921 is 42661.

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

It can be written as a sum of positive squares in 4 ways, for example, as 872552521 + 947408400 = 29539^2 + 30780^2 .

It is not a de Polignac number, because 1819960921 - 2⁹ = 1819960409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1819960981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1577881 + ... + 1579033.

It is an arithmetic number, because the mean of its divisors is an integer number (208011349).

Almost surely, 2^1819960921 is an apocalyptic number.

1819960921 is the 42661-st square number.

1819960921 is the 21331-st centered octagonal number.

It is an amenable number.

1819960921 is a deficient number, since it is larger than the sum of its proper divisors (52141220).

1819960921 is an frugal number, since it uses more digits than its factorization.

1819960921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2380 (or 1190 counting only the distinct ones).

The product of its (nonzero) digits is 69984, while the sum is 46.

The cubic root of 1819960921 is about 1220.9204110963.

The spelling of 1819960921 in words is "one billion, eight hundred nineteen million, nine hundred sixty thousand, nine hundred twenty-one".