21653029 has 4 divisors (see below), whose sum is σ = 22238284. Its totient is φ = 21067776.

The previous prime is 21653011. The next prime is 21653033. The reversal of 21653029 is 92035612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 20657025 + 996004 = 4545^2 + 998^2 .

It is a cyclic number.

It is not a de Polignac number, because 21653029 - 2⁵ = 21652997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21652988 and 21653006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21653039) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 292572 + ... + 292645.

It is an arithmetic number, because the mean of its divisors is an integer number (5559571).

Almost surely, 2^21653029 is an apocalyptic number.

It is an amenable number.

21653029 is a deficient number, since it is larger than the sum of its proper divisors (585255).

21653029 is an equidigital number, since it uses as much as digits as its factorization.

21653029 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 585254.

The product of its (nonzero) digits is 3240, while the sum is 28.

The square root of 21653029 is about 4653.2815302752. The cubic root of 21653029 is about 278.7230500734.

The spelling of 21653029 in words is "twenty-one million, six hundred fifty-three thousand, twenty-nine".