11521021 has 2 divisors, whose sum is σ = 11521022. Its totient is φ = 11521020.

The previous prime is 11521007. The next prime is 11521031. The reversal of 11521021 is 12012511.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11148921 + 372100 = 3339^2 + 610^2 .

It is a cyclic number.

It is not a de Polignac number, because 11521021 - 2²³ = 3132413 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 11520992 and 11521010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11521031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5760510 + 5760511.

It is an arithmetic number, because the mean of its divisors is an integer number (5760511).

Almost surely, 2^11521021 is an apocalyptic number.

It is an amenable number.

11521021 is a deficient number, since it is larger than the sum of its proper divisors (1).

11521021 is an equidigital number, since it uses as much as digits as its factorization.

11521021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20, while the sum is 13.

The square root of 11521021 is about 3394.2629538679. The cubic root of 11521021 is about 225.8553189412.

Adding to 11521021 its reverse (12012511), we get a palindrome (23533532).

The spelling of 11521021 in words is "eleven million, five hundred twenty-one thousand, twenty-one".