21223897 has 4 divisors (see below), whose sum is σ = 21717520. Its totient is φ = 20730276.

The previous prime is 21223889. The next prime is 21223901. The reversal of 21223897 is 79832212.

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 21223897 - 2³ = 21223889 is a prime.

It is a super-3 number, since 3×21223897³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21223297) 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, 246747 + ... + 246832.

It is an arithmetic number, because the mean of its divisors is an integer number (5429380).

Almost surely, 2^21223897 is an apocalyptic number.

It is an amenable number.

21223897 is a deficient number, since it is larger than the sum of its proper divisors (493623).

21223897 is an equidigital number, since it uses as much as digits as its factorization.

21223897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 493622.

The product of its digits is 12096, while the sum is 34.

The square root of 21223897 is about 4606.9400907761. The cubic root of 21223897 is about 276.8694532704.

The spelling of 21223897 in words is "twenty-one million, two hundred twenty-three thousand, eight hundred ninety-seven".