21131002123 has 16 divisors (see below), whose sum is σ = 26351170560. Its totient is φ = 16461950400.

The previous prime is 21131002103. The next prime is 21131002141. The reversal of 21131002123 is 32120013112.

It is not a de Polignac number, because 21131002123 - 2²⁵ = 21097447691 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21131002097 and 21131002106.

It is not an unprimeable number, because it can be changed into a prime (21131002103) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 335118 + ... + 393148.

It is an arithmetic number, because the mean of its divisors is an integer number (1646948160).

Almost surely, 2^21131002123 is an apocalyptic number.

21131002123 is a deficient number, since it is larger than the sum of its proper divisors (5220168437).

21131002123 is a wasteful number, since it uses less digits than its factorization.

21131002123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62778.

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

Adding to 21131002123 its reverse (32120013112), we get a palindrome (53251015235).

The spelling of 21131002123 in words is "twenty-one billion, one hundred thirty-one million, two thousand, one hundred twenty-three".