1820450921 has 2 divisors, whose sum is σ = 1820450922. Its totient is φ = 1820450920.

The previous prime is 1820450887. The next prime is 1820450927. The reversal of 1820450921 is 1290540281.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1819960921 + 490000 = 42661^2 + 700^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1820450921 is a prime.

It is not a weakly prime, because it can be changed into another prime (1820450927) 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 as a sum of consecutive naturals, namely, 910225460 + 910225461.

It is an arithmetic number, because the mean of its divisors is an integer number (910225461).

Almost surely, 2^1820450921 is an apocalyptic number.

It is an amenable number.

1820450921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1820450921 is an equidigital number, since it uses as much as digits as its factorization.

1820450921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5760, while the sum is 32.

The square root of 1820450921 is about 42666.7425637346. The cubic root of 1820450921 is about 1221.0299733974.

The spelling of 1820450921 in words is "one billion, eight hundred twenty million, four hundred fifty thousand, nine hundred twenty-one".