21519168953 has 4 divisors (see below), whose sum is σ = 21519548148. Its totient is φ = 21518789760.

The previous prime is 21519168917. The next prime is 21519169027. The reversal of 21519168953 is 35986191512.

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

It can be written as a sum of positive squares in 2 ways, for example, as 14628176809 + 6890992144 = 120947^2 + 83012^2 .

It is a cyclic number.

It is not a de Polignac number, because 21519168953 - 2⁶ = 21519168889 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21519668953) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85376 + ... + 224337.

It is an arithmetic number, because the mean of its divisors is an integer number (5379887037).

Almost surely, 2^21519168953 is an apocalyptic number.

It is an amenable number.

21519168953 is a deficient number, since it is larger than the sum of its proper divisors (379195).

21519168953 is an equidigital number, since it uses as much as digits as its factorization.

21519168953 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 379194.

The product of its digits is 583200, while the sum is 50.

The spelling of 21519168953 in words is "twenty-one billion, five hundred nineteen million, one hundred sixty-eight thousand, nine hundred fifty-three".