21731437129 has 8 divisors (see below), whose sum is σ = 22623991560. Its totient is φ = 20848429056.

The previous prime is 21731437121. The next prime is 21731437151. The reversal of 21731437129 is 92173413712.

It can be written as a sum of positive squares in 4 ways, for example, as 742671504 + 20988765625 = 27252^2 + 144875^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21731437129 - 2³ = 21731437121 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21731437091 and 21731437100.

It is not an unprimeable number, because it can be changed into a prime (21731437121) 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 7 ways as a sum of consecutive naturals, for example, 2381944 + ... + 2391049.

It is an arithmetic number, because the mean of its divisors is an integer number (2827998945).

Almost surely, 2^21731437129 is an apocalyptic number.

21731437129 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21731437129 is a deficient number, since it is larger than the sum of its proper divisors (892554431).

21731437129 is a wasteful number, since it uses less digits than its factorization.

21731437129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4773179.

The product of its digits is 63504, while the sum is 40.

The spelling of 21731437129 in words is "twenty-one billion, seven hundred thirty-one million, four hundred thirty-seven thousand, one hundred twenty-nine".