21231029 has 2 divisors, whose sum is σ = 21231030. Its totient is φ = 21231028.

The previous prime is 21230969. The next prime is 21231107. The reversal of 21231029 is 92013212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20702500 + 528529 = 4550^2 + 727^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21231029 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21231029.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21231629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615514 + 10615515.

It is an arithmetic number, because the mean of its divisors is an integer number (10615515).

Almost surely, 2^21231029 is an apocalyptic number.

It is an amenable number.

21231029 is a deficient number, since it is larger than the sum of its proper divisors (1).

21231029 is an equidigital number, since it uses as much as digits as its factorization.

21231029 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 21231029 is about 4607.7140753306. The cubic root of 21231029 is about 276.9004625269.

The spelling of 21231029 in words is "twenty-one million, two hundred thirty-one thousand, twenty-nine".