21123144553 has 8 divisors (see below), whose sum is σ = 24362212160. Its totient is φ = 17939445840.

The previous prime is 21123144533. The next prime is 21123144577. The reversal of 21123144553 is 35544132112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21123144553 - 2¹⁷ = 21123013481 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21123144503) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13841403 + ... + 13842928.

It is an arithmetic number, because the mean of its divisors is an integer number (3045276520).

Almost surely, 2^21123144553 is an apocalyptic number.

It is an amenable number.

21123144553 is a deficient number, since it is larger than the sum of its proper divisors (3239067607).

21123144553 is a wasteful number, since it uses less digits than its factorization.

21123144553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27684447.

The product of its digits is 14400, while the sum is 31.

Adding to 21123144553 its reverse (35544132112), we get a palindrome (56667276665).

The spelling of 21123144553 in words is "twenty-one billion, one hundred twenty-three million, one hundred forty-four thousand, five hundred fifty-three".