11551721647 has 2 divisors, whose sum is σ = 11551721648. Its totient is φ = 11551721646.

The previous prime is 11551721543. The next prime is 11551721651. The reversal of 11551721647 is 74612715511.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11551721647 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11551721347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5775860823 + 5775860824.

It is an arithmetic number, because the mean of its divisors is an integer number (5775860824).

Almost surely, 2^11551721647 is an apocalyptic number.

11551721647 is a deficient number, since it is larger than the sum of its proper divisors (1).

11551721647 is an equidigital number, since it uses as much as digits as its factorization.

11551721647 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 58800, while the sum is 40.

The spelling of 11551721647 in words is "eleven billion, five hundred fifty-one million, seven hundred twenty-one thousand, six hundred forty-seven".