21385569 has 8 divisors (see below), whose sum is σ = 28904992. Its totient is φ = 14061600.

The previous prime is 21385549. The next prime is 21385591. The reversal of 21385569 is 96558312.

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

It is not a de Polignac number, because 21385569 - 2⁹ = 21385057 is a prime.

It is a super-2 number, since 2×21385569² = 914685122907522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21385549) 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, 48607 + ... + 49044.

It is an arithmetic number, because the mean of its divisors is an integer number (3613124).

Almost surely, 2^21385569 is an apocalyptic number.

It is an amenable number.

21385569 is a deficient number, since it is larger than the sum of its proper divisors (7519423).

21385569 is an equidigital number, since it uses as much as digits as its factorization.

21385569 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97727.

The product of its digits is 64800, while the sum is 39.

The square root of 21385569 is about 4624.4533731026. The cubic root of 21385569 is about 277.5706889147.

The spelling of 21385569 in words is "twenty-one million, three hundred eighty-five thousand, five hundred sixty-nine".