21123132131 has 4 divisors (see below), whose sum is σ = 21694027632. Its totient is φ = 20552236632.

The previous prime is 21123132109. The next prime is 21123132157. The reversal of 21123132131 is 13123132112.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21123132131 is a prime.

It is a super-2 number, since 2×21123132131² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21123132031) 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, 285447695 + ... + 285447768.

It is an arithmetic number, because the mean of its divisors is an integer number (5423506908).

Almost surely, 2^21123132131 is an apocalyptic number.

21123132131 is a deficient number, since it is larger than the sum of its proper divisors (570895501).

21123132131 is an equidigital number, since it uses as much as digits as its factorization.

21123132131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 570895500.

The product of its digits is 216, while the sum is 20.

Adding to 21123132131 its reverse (13123132112), we get a palindrome (34246264243).

The spelling of 21123132131 in words is "twenty-one billion, one hundred twenty-three million, one hundred thirty-two thousand, one hundred thirty-one".