11655378821 has 2 divisors, whose sum is σ = 11655378822. Its totient is φ = 11655378820.

The previous prime is 11655378809. The next prime is 11655378841. The reversal of 11655378821 is 12887355611.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6676524100 + 4978854721 = 81710^2 + 70561^2 .

It is a cyclic number.

It is not a de Polignac number, because 11655378821 - 2¹⁴ = 11655362437 is a prime.

It is a super-2 number, since 2×11655378821² (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 (11655378841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5827689410 + 5827689411.

It is an arithmetic number, because the mean of its divisors is an integer number (5827689411).

Almost surely, 2^11655378821 is an apocalyptic number.

It is an amenable number.

11655378821 is a deficient number, since it is larger than the sum of its proper divisors (1).

11655378821 is an equidigital number, since it uses as much as digits as its factorization.

11655378821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 403200, while the sum is 47.

The spelling of 11655378821 in words is "eleven billion, six hundred fifty-five million, three hundred seventy-eight thousand, eight hundred twenty-one".