21229969 has 4 divisors (see below), whose sum is σ = 21254896. Its totient is φ = 21205044.

The previous prime is 21229961. The next prime is 21229979. The reversal of 21229969 is 96992212.

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 21229969 - 2³ = 21229961 is a prime.

It is a super-2 number, since 2×21229969² = 901423167481922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21229961) 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, 11139 + ... + 12904.

It is an arithmetic number, because the mean of its divisors is an integer number (5313724).

Almost surely, 2^21229969 is an apocalyptic number.

It is an amenable number.

21229969 is a deficient number, since it is larger than the sum of its proper divisors (24927).

21229969 is an equidigital number, since it uses as much as digits as its factorization.

21229969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24926.

The product of its digits is 34992, while the sum is 40.

The square root of 21229969 is about 4607.5990493966. The cubic root of 21229969 is about 276.8958541873.

The spelling of 21229969 in words is "twenty-one million, two hundred twenty-nine thousand, nine hundred sixty-nine".