21320897 has 8 divisors (see below), whose sum is σ = 23185344. Its totient is φ = 19488528.

The previous prime is 21320881. The next prime is 21320911. The reversal of 21320897 is 79802312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21320897 - 2⁴ = 21320881 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21320837) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6623 + ... + 9300.

It is an arithmetic number, because the mean of its divisors is an integer number (2898168).

Almost surely, 2^21320897 is an apocalyptic number.

It is an amenable number.

21320897 is a deficient number, since it is larger than the sum of its proper divisors (1864447).

21320897 is a wasteful number, since it uses less digits than its factorization.

21320897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16039.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 21320897 is about 4617.4556846818. The cubic root of 21320897 is about 277.2906063150.

The spelling of 21320897 in words is "twenty-one million, three hundred twenty thousand, eight hundred ninety-seven".