21669297 has 16 divisors (see below), whose sum is σ = 31321920. Its totient is φ = 13246272.

The previous prime is 21669281. The next prime is 21669299. The reversal of 21669297 is 79296612.

It is not a de Polignac number, because 21669297 - 2⁴ = 21669281 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21669299) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4354 + ... + 7892.

It is an arithmetic number, because the mean of its divisors is an integer number (1957620).

Almost surely, 2^21669297 is an apocalyptic number.

It is an amenable number.

21669297 is a deficient number, since it is larger than the sum of its proper divisors (9652623).

21669297 is a wasteful number, since it uses less digits than its factorization.

21669297 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3712.

The product of its digits is 81648, while the sum is 42.

The square root of 21669297 is about 4655.0292158052. The cubic root of 21669297 is about 278.7928344827.

The spelling of 21669297 in words is "twenty-one million, six hundred sixty-nine thousand, two hundred ninety-seven".