21029629 has 4 divisors (see below), whose sum is σ = 22266684. Its totient is φ = 19792576.

The previous prime is 21029587. The next prime is 21029641. The reversal of 21029629 is 92692012.

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 12089529 + 8940100 = 3477^2 + 2990^2 .

It is a cyclic number.

It is not a de Polignac number, because 21029629 - 2¹⁹ = 20505341 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21029629.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 618502 + ... + 618535.

It is an arithmetic number, because the mean of its divisors is an integer number (5566671).

Almost surely, 2^21029629 is an apocalyptic number.

It is an amenable number.

21029629 is a deficient number, since it is larger than the sum of its proper divisors (1237055).

21029629 is a wasteful number, since it uses less digits than its factorization.

21029629 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1237054.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 21029629 is about 4585.8073444051. The cubic root of 21029629 is about 276.0221093050.

The spelling of 21029629 in words is "twenty-one million, twenty-nine thousand, six hundred twenty-nine".