21250129 has 2 divisors, whose sum is σ = 21250130. Its totient is φ = 21250128.

The previous prime is 21250123. The next prime is 21250133. The reversal of 21250129 is 92105212.

21250129 is nontrivially palindromic in base 8.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15000129 + 6250000 = 3873^2 + 2500^2 .

It is a cyclic number.

It is not a de Polignac number, because 21250129 - 2³ = 21250121 is a prime.

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

It is not a weakly prime, because it can be changed into another prime (21250121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10625064 + 10625065.

It is an arithmetic number, because the mean of its divisors is an integer number (10625065).

Almost surely, 2^21250129 is an apocalyptic number.

It is an amenable number.

21250129 is a deficient number, since it is larger than the sum of its proper divisors (1).

21250129 is an equidigital number, since it uses as much as digits as its factorization.

21250129 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 21250129 is about 4609.7862206397. The cubic root of 21250129 is about 276.9834733197.

The spelling of 21250129 in words is "twenty-one million, two hundred fifty thousand, one hundred twenty-nine".