11721521069 has 2 divisors, whose sum is σ = 11721521070. Its totient is φ = 11721521068.

The previous prime is 11721521047. The next prime is 11721521081. The reversal of 11721521069 is 96012512711.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6713835844 + 5007685225 = 81938^2 + 70765^2 .

It is a cyclic number.

It is not a de Polignac number, because 11721521069 - 2¹² = 11721516973 is a prime.

It is a super-2 number, since 2×11721521069² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11751521069) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5860760534 + 5860760535.

It is an arithmetic number, because the mean of its divisors is an integer number (5860760535).

Almost surely, 2^11721521069 is an apocalyptic number.

It is an amenable number.

11721521069 is a deficient number, since it is larger than the sum of its proper divisors (1).

11721521069 is an equidigital number, since it uses as much as digits as its factorization.

11721521069 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7560, while the sum is 35.

The spelling of 11721521069 in words is "eleven billion, seven hundred twenty-one million, five hundred twenty-one thousand, sixty-nine".