21130012123 has 4 divisors (see below), whose sum is σ = 23050922328. Its totient is φ = 19209101920.

The previous prime is 21130012121. The next prime is 21130012153. The reversal of 21130012123 is 32121003112.

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

It is a cyclic number.

It is not a de Polignac number, because 21130012123 - 2¹ = 21130012121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21130012097 and 21130012106.

It is not an unprimeable number, because it can be changed into a prime (21130012121) 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, 960455086 + ... + 960455107.

It is an arithmetic number, because the mean of its divisors is an integer number (5762730582).

Almost surely, 2^21130012123 is an apocalyptic number.

21130012123 is a deficient number, since it is larger than the sum of its proper divisors (1920910205).

21130012123 is a wasteful number, since it uses less digits than its factorization.

21130012123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1920910204.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21130012123 its reverse (32121003112), we get a palindrome (53251015235).

The spelling of 21130012123 in words is "twenty-one billion, one hundred thirty million, twelve thousand, one hundred twenty-three".