21153123023 has 16 divisors (see below), whose sum is σ = 22308302016. Its totient is φ = 20018718720.

The previous prime is 21153123011. The next prime is 21153123053. The reversal of 21153123023 is 32032135112.

It is a cyclic number.

It is not a de Polignac number, because 21153123023 - 2¹⁰ = 21153121999 is a prime.

It is a super-2 number, since 2×21153123023² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21153123023.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21153123053) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 807215 + ... + 833007.

It is an arithmetic number, because the mean of its divisors is an integer number (1394268876).

Almost surely, 2^21153123023 is an apocalyptic number.

21153123023 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21153123023 is a deficient number, since it is larger than the sum of its proper divisors (1155178993).

21153123023 is a wasteful number, since it uses less digits than its factorization.

21153123023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26194.

The product of its (nonzero) digits is 1080, while the sum is 23.

Adding to 21153123023 its reverse (32032135112), we get a palindrome (53185258135).

The spelling of 21153123023 in words is "twenty-one billion, one hundred fifty-three million, one hundred twenty-three thousand, twenty-three".