21554410145 has 4 divisors (see below), whose sum is σ = 25865292180. Its totient is φ = 17243528112.

The previous prime is 21554410139. The next prime is 21554410151. The reversal of 21554410145 is 54101445512.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21554410139) and next prime (21554410151).

It can be written as a sum of positive squares in 2 ways, for example, as 13029765904 + 8524644241 = 114148^2 + 92329^2 .

It is a cyclic number.

It is not a de Polignac number, because 21554410145 - 2⁸ = 21554409889 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2155441010 + ... + 2155441019.

It is an arithmetic number, because the mean of its divisors is an integer number (6466323045).

Almost surely, 2^21554410145 is an apocalyptic number.

It is an amenable number.

21554410145 is a deficient number, since it is larger than the sum of its proper divisors (4310882035).

21554410145 is an equidigital number, since it uses as much as digits as its factorization.

21554410145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4310882034.

The product of its (nonzero) digits is 16000, while the sum is 32.

Adding to 21554410145 its reverse (54101445512), we get a palindrome (75655855657).

The spelling of 21554410145 in words is "twenty-one billion, five hundred fifty-four million, four hundred ten thousand, one hundred forty-five".