21006629 has 4 divisors (see below), whose sum is σ = 24007584. Its totient is φ = 18005676.

The previous prime is 21006619. The next prime is 21006641. The reversal of 21006629 is 92660012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21006629 - 2²⁰ = 19958053 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21006598 and 21006607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21006619) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1500467 + ... + 1500480.

It is an arithmetic number, because the mean of its divisors is an integer number (6001896).

Almost surely, 2^21006629 is an apocalyptic number.

It is an amenable number.

21006629 is a deficient number, since it is larger than the sum of its proper divisors (3000955).

21006629 is an equidigital number, since it uses as much as digits as its factorization.

21006629 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3000954.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 21006629 is about 4583.2989210829. The cubic root of 21006629 is about 275.9214445973.

The spelling of 21006629 in words is "twenty-one million, six thousand, six hundred twenty-nine".