21617629 has 4 divisors (see below), whose sum is σ = 23582880. Its totient is φ = 19652380.

The previous prime is 21617627. The next prime is 21617653. The reversal of 21617629 is 92671612.

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 not a de Polignac number, because 21617629 - 2¹ = 21617627 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21617594 and 21617603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21617621) 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, 982609 + ... + 982630.

It is an arithmetic number, because the mean of its divisors is an integer number (5895720).

Almost surely, 2^21617629 is an apocalyptic number.

It is an amenable number.

21617629 is a deficient number, since it is larger than the sum of its proper divisors (1965251).

21617629 is a wasteful number, since it uses less digits than its factorization.

21617629 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1965250.

The product of its digits is 9072, while the sum is 34.

The square root of 21617629 is about 4649.4762070582. The cubic root of 21617629 is about 278.5710747561.

The spelling of 21617629 in words is "twenty-one million, six hundred seventeen thousand, six hundred twenty-nine".