21554115547 has 2 divisors, whose sum is σ = 21554115548. Its totient is φ = 21554115546.

The previous prime is 21554115529. The next prime is 21554115559. The reversal of 21554115547 is 74551145512.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21554115547 - 2¹¹ = 21554113499 is a prime.

It is not a weakly prime, because it can be changed into another prime (21554115647) 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, 10777057773 + 10777057774.

It is an arithmetic number, because the mean of its divisors is an integer number (10777057774).

Almost surely, 2^21554115547 is an apocalyptic number.

21554115547 is a deficient number, since it is larger than the sum of its proper divisors (1).

21554115547 is an equidigital number, since it uses as much as digits as its factorization.

21554115547 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 140000, while the sum is 40.

The spelling of 21554115547 in words is "twenty-one billion, five hundred fifty-four million, one hundred fifteen thousand, five hundred forty-seven".