21454253505 has 24 divisors (see below), whose sum is σ = 38469698280. Its totient is φ = 11047706880.

The previous prime is 21454253501. The next prime is 21454253519. The reversal of 21454253505 is 50535245412.

21454253505 is a `hidden beast` number, since 2 + 14 + 542 + 53 + 50 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 14265729 + 21439987776 = 3777^2 + 146424^2 .

It is not a de Polignac number, because 21454253505 - 2² = 21454253501 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21454253505.

It is not an unprimeable number, because it can be changed into a prime (21454253501) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8218716 + ... + 8221325.

It is an arithmetic number, because the mean of its divisors is an integer number (1602904095).

Almost surely, 2^21454253505 is an apocalyptic number.

It is an amenable number.

21454253505 is a deficient number, since it is larger than the sum of its proper divisors (17015444775).

21454253505 is a wasteful number, since it uses less digits than its factorization.

21454253505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16440081 (or 16440078 counting only the distinct ones).

The product of its (nonzero) digits is 120000, while the sum is 36.

Adding to 21454253505 its reverse (50535245412), we get a palindrome (71989498917).

The spelling of 21454253505 in words is "twenty-one billion, four hundred fifty-four million, two hundred fifty-three thousand, five hundred five".