21316569 has 8 divisors (see below), whose sum is σ = 28646400. Its totient is φ = 14098896.

The previous prime is 21316553. The next prime is 21316579. The reversal of 21316569 is 96561312.

It is a happy number.

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

It is not a de Polignac number, because 21316569 - 2⁴ = 21316553 is a prime.

It is a super-2 number, since 2×21316569² = 908792227863522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21316579) 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, 27594 + ... + 28355.

It is an arithmetic number, because the mean of its divisors is an integer number (3580800).

Almost surely, 2^21316569 is an apocalyptic number.

It is an amenable number.

21316569 is a deficient number, since it is larger than the sum of its proper divisors (7329831).

21316569 is a wasteful number, since it uses less digits than its factorization.

21316569 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56079.

The product of its digits is 9720, while the sum is 33.

The square root of 21316569 is about 4616.9870045301. The cubic root of 21316569 is about 277.2718423302.

The spelling of 21316569 in words is "twenty-one million, three hundred sixteen thousand, five hundred sixty-nine".