21291629 has 8 divisors (see below), whose sum is σ = 22349952. Its totient is φ = 20244400.

The previous prime is 21291593. The next prime is 21291643. The reversal of 21291629 is 92619212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21291629 - 2⁸ = 21291373 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21291595 and 21291604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21291689) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1304 + ... + 6654.

It is an arithmetic number, because the mean of its divisors is an integer number (2793744).

Almost surely, 2^21291629 is an apocalyptic number.

It is an amenable number.

21291629 is a deficient number, since it is larger than the sum of its proper divisors (1058323).

21291629 is a wasteful number, since it uses less digits than its factorization.

21291629 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5547.

The product of its digits is 3888, while the sum is 32.

The square root of 21291629 is about 4614.2853184431. The cubic root of 21291629 is about 277.1636657850.

The spelling of 21291629 in words is "twenty-one million, two hundred ninety-one thousand, six hundred twenty-nine".