1805329921 has 2 divisors, whose sum is σ = 1805329922. Its totient is φ = 1805329920.

The previous prime is 1805329907. The next prime is 1805329927. The reversal of 1805329921 is 1299235081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1603121521 + 202208400 = 40039^2 + 14220^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1805329921 is a prime.

It is a super-2 number, since 2×1805329921² = 6518432247315732482, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1805329927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 902664960 + 902664961.

It is an arithmetic number, because the mean of its divisors is an integer number (902664961).

Almost surely, 2^1805329921 is an apocalyptic number.

It is an amenable number.

1805329921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1805329921 is an equidigital number, since it uses as much as digits as its factorization.

1805329921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 38880, while the sum is 40.

The square root of 1805329921 is about 42489.1741623675. The cubic root of 1805329921 is about 1217.6398699192.

It can be divided in two parts, 18053 and 29921, that added together give a palindrome (47974).

The spelling of 1805329921 in words is "one billion, eight hundred five million, three hundred twenty-nine thousand, nine hundred twenty-one".