21384829 has 2 divisors, whose sum is σ = 21384830. Its totient is φ = 21384828.

The previous prime is 21384817. The next prime is 21384841. The reversal of 21384829 is 92848312.

It is a balanced prime because it is at equal distance from previous prime (21384817) and next prime (21384841).

It can be written as a sum of positive squares in only one way, i.e., 20748025 + 636804 = 4555^2 + 798^2 .

It is a cyclic number.

It is not a de Polignac number, because 21384829 - 2¹⁵ = 21352061 is a prime.

It is a super-2 number, since 2×21384829² = 914621822718482, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21384809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10692414 + 10692415.

It is an arithmetic number, because the mean of its divisors is an integer number (10692415).

Almost surely, 2^21384829 is an apocalyptic number.

It is an amenable number.

21384829 is a deficient number, since it is larger than the sum of its proper divisors (1).

21384829 is an equidigital number, since it uses as much as digits as its factorization.

21384829 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27648, while the sum is 37.

The square root of 21384829 is about 4624.3733629542. The cubic root of 21384829 is about 277.5674873059.

It can be divided in two parts, 2 and 1384829, that added together give a palindrome (1384831).

The spelling of 21384829 in words is "twenty-one million, three hundred eighty-four thousand, eight hundred twenty-nine".