21026629 has 4 divisors (see below), whose sum is σ = 22644076. Its totient is φ = 19409184.

The previous prime is 21026627. The next prime is 21026633. The reversal of 21026629 is 92662012.

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 5832225 + 15194404 = 2415^2 + 3898^2 .

It is a cyclic number.

It is not a de Polignac number, because 21026629 - 2¹ = 21026627 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21026597 and 21026606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21026627) 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, 808704 + ... + 808729.

It is an arithmetic number, because the mean of its divisors is an integer number (5661019).

Almost surely, 2^21026629 is an apocalyptic number.

It is an amenable number.

21026629 is a deficient number, since it is larger than the sum of its proper divisors (1617447).

21026629 is a wasteful number, since it uses less digits than its factorization.

21026629 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1617446.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 21026629 is about 4585.4802365728. The cubic root of 21026629 is about 276.0089832895.

The spelling of 21026629 in words is "twenty-one million, twenty-six thousand, six hundred twenty-nine".