11561421649 has 2 divisors, whose sum is σ = 11561421650. Its totient is φ = 11561421648.

The previous prime is 11561421631. The next prime is 11561421731. The reversal of 11561421649 is 94612416511.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6539148225 + 5022273424 = 80865^2 + 70868^2 .

It is a cyclic number.

It is not a de Polignac number, because 11561421649 - 2⁵ = 11561421617 is a prime.

It is not a weakly prime, because it can be changed into another prime (11561421629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5780710824 + 5780710825.

It is an arithmetic number, because the mean of its divisors is an integer number (5780710825).

Almost surely, 2^11561421649 is an apocalyptic number.

It is an amenable number.

11561421649 is a deficient number, since it is larger than the sum of its proper divisors (1).

11561421649 is an equidigital number, since it uses as much as digits as its factorization.

11561421649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 51840, while the sum is 40.

The spelling of 11561421649 in words is "eleven billion, five hundred sixty-one million, four hundred twenty-one thousand, six hundred forty-nine".