20911229 has 4 divisors (see below), whose sum is σ = 22011840. Its totient is φ = 19810620.

The previous prime is 20911223. The next prime is 20911243. The reversal of 20911229 is 92211902.

It is a happy number.

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 a cyclic number.

It is not a de Polignac number, because 20911229 - 2⁴ = 20911213 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 13.

It is a junction number, because it is equal to n+sod(n) for n = 20911198 and 20911207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20911223) 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, 550277 + ... + 550314.

It is an arithmetic number, because the mean of its divisors is an integer number (5502960).

Almost surely, 2^20911229 is an apocalyptic number.

It is an amenable number.

20911229 is a deficient number, since it is larger than the sum of its proper divisors (1100611).

20911229 is a wasteful number, since it uses less digits than its factorization.

20911229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1100610.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 20911229 is about 4572.8797272616. The cubic root of 20911229 is about 275.5031186413.

It can be divided in two parts, 209 and 11229, that multiplied together give a triangular number (2346861 = T₂₁₆₆).

The spelling of 20911229 in words is "twenty million, nine hundred eleven thousand, two hundred twenty-nine".