21153144505 has 64 divisors (see below), whose sum is σ = 28356157440. Its totient is φ = 15076233216.

The previous prime is 21153144491. The next prime is 21153144527. The reversal of 21153144505 is 50544135112.

It is a cyclic number.

It is not a de Polignac number, because 21153144505 - 2⁹ = 21153143993 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 43435372 + ... + 43435858.

It is an arithmetic number, because the mean of its divisors is an integer number (443064960).

Almost surely, 2^21153144505 is an apocalyptic number.

It is an amenable number.

21153144505 is a deficient number, since it is larger than the sum of its proper divisors (7203012935).

21153144505 is a wasteful number, since it uses less digits than its factorization.

21153144505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 830.

The product of its (nonzero) digits is 12000, while the sum is 31.

Adding to 21153144505 its reverse (50544135112), we get a palindrome (71697279617).

It can be divided in two parts, 211531 and 44505, that added together give a square (256036 = 506²).

The spelling of 21153144505 in words is "twenty-one billion, one hundred fifty-three million, one hundred forty-four thousand, five hundred five".