21628629 has 18 divisors (see below), whose sum is σ = 34341398. Its totient is φ = 13107600.

The previous prime is 21628627. The next prime is 21628643. The reversal of 21628629 is 92682612.

It is a happy number.

21628629 is a `hidden beast` number, since 2 + 1 + 6 + 28 + 629 = 666.

It can be written as a sum of positive squares in only one way, i.e., 12006225 + 9622404 = 3465^2 + 3102^2 .

It is not a de Polignac number, because 21628629 - 2¹ = 21628627 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21628593 and 21628602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21628627) 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 17 ways as a sum of consecutive naturals, for example, 8842 + ... + 11019.

Almost surely, 2^21628629 is an apocalyptic number.

It is an amenable number.

21628629 is a deficient number, since it is larger than the sum of its proper divisors (12712769).

21628629 is a wasteful number, since it uses less digits than its factorization.

21628629 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19889 (or 19875 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 21628629 is about 4650.6589855632. The cubic root of 21628629 is about 278.6183164807.

The spelling of 21628629 in words is "twenty-one million, six hundred twenty-eight thousand, six hundred twenty-nine".