1840813721 has 2 divisors, whose sum is σ = 1840813722. Its totient is φ = 1840813720.

The previous prime is 1840813699. The next prime is 1840813729. The reversal of 1840813721 is 1273180481.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1368186121 + 472627600 = 36989^2 + 21740^2 .

It is a cyclic number.

It is not a de Polignac number, because 1840813721 - 2¹⁴ = 1840797337 is a prime.

It is not a weakly prime, because it can be changed into another prime (1840813729) 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 as a sum of consecutive naturals, namely, 920406860 + 920406861.

It is an arithmetic number, because the mean of its divisors is an integer number (920406861).

Almost surely, 2^1840813721 is an apocalyptic number.

It is an amenable number.

1840813721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1840813721 is an equidigital number, since it uses as much as digits as its factorization.

1840813721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10752, while the sum is 35.

The square root of 1840813721 is about 42904.7051149405. The cubic root of 1840813721 is about 1225.5657463980.

The spelling of 1840813721 in words is "one billion, eight hundred forty million, eight hundred thirteen thousand, seven hundred twenty-one".