21000122131 has 4 divisors (see below), whose sum is σ = 21153407832. Its totient is φ = 20846836432.

The previous prime is 21000122113. The next prime is 21000122161. The reversal of 21000122131 is 13122100012.

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 21000122131 - 2⁹ = 21000121619 is a prime.

It is a super-2 number, since 2×21000122131² (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 (21000122111) 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 3 ways as a sum of consecutive naturals, for example, 76642645 + ... + 76642918.

It is an arithmetic number, because the mean of its divisors is an integer number (5288351958).

Almost surely, 2^21000122131 is an apocalyptic number.

21000122131 is a deficient number, since it is larger than the sum of its proper divisors (153285701).

21000122131 is a wasteful number, since it uses less digits than its factorization.

21000122131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153285700.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21000122131 its reverse (13122100012), we get a palindrome (34122222143).

The spelling of 21000122131 in words is "twenty-one billion, one hundred twenty-two thousand, one hundred thirty-one".