21504844953 has 10 divisors (see below), whose sum is σ = 32124521594. Its totient is φ = 14336563248.

The previous prime is 21504844951. The next prime is 21504844961. The reversal of 21504844953 is 35944840512.

21504844953 is a `hidden beast` number, since 2 + 150 + 4 + 8 + 4 + 495 + 3 = 666.

It can be written as a sum of positive squares in only one way, i.e., 13122160704 + 8382684249 = 114552^2 + 91557^2 .

It is not a de Polignac number, because 21504844953 - 2¹ = 21504844951 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21504844899 and 21504844908.

It is not an unprimeable number, because it can be changed into a prime (21504844951) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 132745876 + ... + 132746037.

Almost surely, 2^21504844953 is an apocalyptic number.

It is an amenable number.

21504844953 is a deficient number, since it is larger than the sum of its proper divisors (10619676641).

21504844953 is an equidigital number, since it uses as much as digits as its factorization.

21504844953 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 265491925 (or 265491916 counting only the distinct ones).

The product of its (nonzero) digits is 691200, while the sum is 45.

The spelling of 21504844953 in words is "twenty-one billion, five hundred four million, eight hundred forty-four thousand, nine hundred fifty-three".