21942229 has 4 divisors (see below), whose sum is σ = 21952000. Its totient is φ = 21932460.

The previous prime is 21942209. The next prime is 21942251. The reversal of 21942229 is 92224912.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21942229 - 2¹⁷ = 21811157 is a prime.

It is a super-2 number, since 2×21942229² = 962922826976882, which contains 22 as substring.

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 21942229.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21942209) 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, 364 + ... + 6634.

It is an arithmetic number, because the mean of its divisors is an integer number (5488000).

Almost surely, 2^21942229 is an apocalyptic number.

It is an amenable number.

21942229 is a deficient number, since it is larger than the sum of its proper divisors (9771).

21942229 is an equidigital number, since it uses as much as digits as its factorization.

21942229 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9770.

The product of its digits is 5184, while the sum is 31.

The square root of 21942229 is about 4684.2533022884. The cubic root of 21942229 is about 279.9584504674.

The spelling of 21942229 in words is "twenty-one million, nine hundred forty-two thousand, two hundred twenty-nine".