11205721 has 2 divisors, whose sum is σ = 11205722. Its totient is φ = 11205720.

The previous prime is 11205707. The next prime is 11205739. The reversal of 11205721 is 12750211.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8094025 + 3111696 = 2845^2 + 1764^2 .

It is a cyclic number.

It is not a de Polignac number, because 11205721 - 2²¹ = 9108569 is a prime.

It is a nialpdrome in base 15.

It is not a weakly prime, because it can be changed into another prime (11205791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5602860 + 5602861.

It is an arithmetic number, because the mean of its divisors is an integer number (5602861).

Almost surely, 2^11205721 is an apocalyptic number.

It is an amenable number.

11205721 is a deficient number, since it is larger than the sum of its proper divisors (1).

11205721 is an equidigital number, since it uses as much as digits as its factorization.

11205721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 140, while the sum is 19.

The square root of 11205721 is about 3347.4947348726. The cubic root of 11205721 is about 223.7758772855.

Adding to 11205721 its reverse (12750211), we get a palindrome (23955932).

The spelling of 11205721 in words is "eleven million, two hundred five thousand, seven hundred twenty-one".