21050129 has 4 divisors (see below), whose sum is σ = 21965376. Its totient is φ = 20134884.

The previous prime is 21050111. The next prime is 21050137. The reversal of 21050129 is 92105012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21050129 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21050129.

It is not an unprimeable number, because it can be changed into a prime (21050149) 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, 457589 + ... + 457634.

It is an arithmetic number, because the mean of its divisors is an integer number (5491344).

Almost surely, 2^21050129 is an apocalyptic number.

It is an amenable number.

21050129 is a deficient number, since it is larger than the sum of its proper divisors (915247).

21050129 is an equidigital number, since it uses as much as digits as its factorization.

21050129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 915246.

The product of its (nonzero) digits is 180, while the sum is 20.

The square root of 21050129 is about 4588.0419570880. The cubic root of 21050129 is about 276.1117703508. Note that the first 3 decimals are identical.

The spelling of 21050129 in words is "twenty-one million, fifty thousand, one hundred twenty-nine".