805721101 has 2 divisors, whose sum is σ = 805721102. Its totient is φ = 805721100.

The previous prime is 805721083. The next prime is 805721113. The reversal of 805721101 is 101127508.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 727380900 + 78340201 = 26970^2 + 8851^2 .

It is a cyclic number.

It is not a de Polignac number, because 805721101 - 2¹⁷ = 805590029 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (805721131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 402860550 + 402860551.

It is an arithmetic number, because the mean of its divisors is an integer number (402860551).

Almost surely, 2^805721101 is an apocalyptic number.

It is an amenable number.

805721101 is a deficient number, since it is larger than the sum of its proper divisors (1).

805721101 is an equidigital number, since it uses as much as digits as its factorization.

805721101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 560, while the sum is 25.

The square root of 805721101 is about 28385.2268090287. The cubic root of 805721101 is about 930.5254289914.

Adding to 805721101 its reverse (101127508), we get a palindrome (906848609).

The spelling of 805721101 in words is "eight hundred five million, seven hundred twenty-one thousand, one hundred one".