21717369 has 16 divisors (see below), whose sum is σ = 32721600. Its totient is φ = 14231808.

The previous prime is 21717307. The next prime is 21717373. The reversal of 21717369 is 96371712.

It is a happy number.

It is not a de Polignac number, because 21717369 - 2⁹ = 21716857 is a prime.

It is a super-2 number, since 2×21717369² = 943288232564322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21717169) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5224 + ... + 8409.

It is an arithmetic number, because the mean of its divisors is an integer number (2045100).

Almost surely, 2^21717369 is an apocalyptic number.

It is an amenable number.

21717369 is a deficient number, since it is larger than the sum of its proper divisors (11004231).

21717369 is a wasteful number, since it uses less digits than its factorization.

21717369 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13701 (or 13695 counting only the distinct ones).

The product of its digits is 15876, while the sum is 36.

The square root of 21717369 is about 4660.1898030016. The cubic root of 21717369 is about 278.9988437922.

The spelling of 21717369 in words is "twenty-one million, seven hundred seventeen thousand, three hundred sixty-nine".