21820029 has 32 divisors (see below), whose sum is σ = 36910080. Its totient is φ = 11136000.

The previous prime is 21820013. The next prime is 21820033. The reversal of 21820029 is 92002812.

It is not a de Polignac number, because 21820029 - 2⁴ = 21820013 is a prime.

It is a super-2 number, since 2×21820029² = 952227331121682, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21819990 and 21820008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21820069) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12829 + ... + 14429.

It is an arithmetic number, because the mean of its divisors is an integer number (1153440).

Almost surely, 2^21820029 is an apocalyptic number.

It is an amenable number.

21820029 is a deficient number, since it is larger than the sum of its proper divisors (15090051).

21820029 is a wasteful number, since it uses less digits than its factorization.

21820029 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1681.

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 21820029 is about 4671.1913897848. The cubic root of 21820029 is about 279.4377706299.

The spelling of 21820029 in words is "twenty-one million, eight hundred twenty thousand, twenty-nine".