21000012131 has 16 divisors (see below), whose sum is σ = 24415776000. Its totient is φ = 17688414048.

The previous prime is 21000012113. The next prime is 21000012199. The reversal of 21000012131 is 13121000012.

It is a cyclic number.

It is not a de Polignac number, because 21000012131 - 2¹⁴ = 20999995747 is a prime.

It is a super-2 number, since 2×21000012131² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21000012431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1354781 + ... + 1370193.

It is an arithmetic number, because the mean of its divisors is an integer number (1525986000).

Almost surely, 2^21000012131 is an apocalyptic number.

21000012131 is a deficient number, since it is larger than the sum of its proper divisors (3415763869).

21000012131 is a wasteful number, since it uses less digits than its factorization.

21000012131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18778.

The product of its (nonzero) digits is 12, while the sum is 11.

Adding to 21000012131 its reverse (13121000012), we get a palindrome (34121012143).

It can be divided in two parts, 21000012 and 131, that multiplied together give a palindrome (2751001572).

The spelling of 21000012131 in words is "twenty-one billion, twelve thousand, one hundred thirty-one".