20216129 has 4 divisors (see below), whose sum is σ = 20225220. Its totient is φ = 20207040.

The previous prime is 20216099. The next prime is 20216137. The reversal of 20216129 is 92161202.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 17205904 + 3010225 = 4148^2 + 1735^2 .

It is a cyclic number.

It is not a de Polignac number, because 20216129 - 2¹² = 20212033 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20218129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1277 + ... + 6485.

It is an arithmetic number, because the mean of its divisors is an integer number (5056305).

Almost surely, 2^20216129 is an apocalyptic number.

It is an amenable number.

20216129 is a deficient number, since it is larger than the sum of its proper divisors (9091).

20216129 is an equidigital number, since it uses as much as digits as its factorization.

20216129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9090.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 20216129 is about 4496.2349805143. The cubic root of 20216129 is about 272.4160345069.

The spelling of 20216129 in words is "twenty million, two hundred sixteen thousand, one hundred twenty-nine".