21712229 has 16 divisors (see below), whose sum is σ = 27805056. Its totient is φ = 16459200.

The previous prime is 21712211. The next prime is 21712237. The reversal of 21712229 is 92221712.

It is a cyclic number.

It is not a de Polignac number, because 21712229 - 2⁸ = 21711973 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21712198 and 21712207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21712259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 962 + ... + 6659.

It is an arithmetic number, because the mean of its divisors is an integer number (1737816).

Almost surely, 2^21712229 is an apocalyptic number.

It is an amenable number.

21712229 is a deficient number, since it is larger than the sum of its proper divisors (6092827).

21712229 is a wasteful number, since it uses less digits than its factorization.

21712229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7676.

The product of its digits is 1008, while the sum is 26.

The square root of 21712229 is about 4659.6382906831. The cubic root of 21712229 is about 278.9768311931.

The spelling of 21712229 in words is "twenty-one million, seven hundred twelve thousand, two hundred twenty-nine".