21080829 has 24 divisors (see below), whose sum is σ = 35671968. Its totient is φ = 10950240.

The previous prime is 21080797. The next prime is 21080831. The reversal of 21080829 is 92808012.

It is not a de Polignac number, because 21080829 - 2⁵ = 21080797 is a prime.

It is a super-4 number, since 4×21080829⁴ (a number of 30 digits) contains 4444 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21080796 and 21080805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21080849) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4902 + ... + 8135.

It is an arithmetic number, because the mean of its divisors is an integer number (1486332).

Almost surely, 2^21080829 is an apocalyptic number.

It is an amenable number.

21080829 is a deficient number, since it is larger than the sum of its proper divisors (14591139).

21080829 is a wasteful number, since it uses less digits than its factorization.

21080829 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13065 (or 13058 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 30.

The square root of 21080829 is about 4591.3863919300. The cubic root of 21080829 is about 276.2459344351.

The spelling of 21080829 in words is "twenty-one million, eighty thousand, eight hundred twenty-nine".