11605220021 has 2 divisors, whose sum is σ = 11605220022. Its totient is φ = 11605220020.

The previous prime is 11605219999. The next prime is 11605220057. The reversal of 11605220021 is 12002250611.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6180160996 + 5425059025 = 78614^2 + 73655^2 .

It is a cyclic number.

It is not a de Polignac number, because 11605220021 - 2⁶ = 11605219957 is a prime.

It is a super-2 number, since 2×11605220021² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 11605219975 and 11605220002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11605220071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5802610010 + 5802610011.

It is an arithmetic number, because the mean of its divisors is an integer number (5802610011).

Almost surely, 2^11605220021 is an apocalyptic number.

It is an amenable number.

11605220021 is a deficient number, since it is larger than the sum of its proper divisors (1).

11605220021 is an equidigital number, since it uses as much as digits as its factorization.

11605220021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 240, while the sum is 20.

Adding to 11605220021 its reverse (12002250611), we get a palindrome (23607470632).

The spelling of 11605220021 in words is "eleven billion, six hundred five million, two hundred twenty thousand, twenty-one".