1805146721 has 6 divisors (see below), whose sum is σ = 2099864610. Its totient is φ = 1547268576.

The previous prime is 1805146691. The next prime is 1805146727. The reversal of 1805146721 is 1276415081.

It can be written as a sum of positive squares in only one way, i.e., 1675756096 + 129390625 = 40936^2 + 11375^2 .

It is not a de Polignac number, because 1805146721 - 2¹⁴ = 1805130337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1805146727) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 18419816 + ... + 18419913.

It is an arithmetic number, because the mean of its divisors is an integer number (349977435).

Almost surely, 2^1805146721 is an apocalyptic number.

It is an amenable number.

1805146721 is a deficient number, since it is larger than the sum of its proper divisors (294717889).

1805146721 is an equidigital number, since it uses as much as digits as its factorization.

1805146721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36839743 (or 36839736 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 35.

The square root of 1805146721 is about 42487.0182644064. The cubic root of 1805146721 is about 1217.5986809251.

The spelling of 1805146721 in words is "one billion, eight hundred five million, one hundred forty-six thousand, seven hundred twenty-one".