20691229 has 8 divisors (see below), whose sum is σ = 23002112. Its totient is φ = 18483120.

The previous prime is 20691217. The next prime is 20691259. The reversal of 20691229 is 92219602.

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 20691229 - 2⁵ = 20691197 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

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 20691229.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20691259) 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, 25269 + ... + 26074.

It is an arithmetic number, because the mean of its divisors is an integer number (2875264).

Almost surely, 2^20691229 is an apocalyptic number.

It is an amenable number.

20691229 is a deficient number, since it is larger than the sum of its proper divisors (2310883).

20691229 is a wasteful number, since it uses less digits than its factorization.

20691229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51387.

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

The square root of 20691229 is about 4548.7612599476. The cubic root of 20691229 is about 274.5335519697.

The spelling of 20691229 in words is "twenty million, six hundred ninety-one thousand, two hundred twenty-nine".