21000385 has 8 divisors (see below), whose sum is σ = 28800576. Its totient is φ = 14400240.

The previous prime is 21000367. The next prime is 21000391. The reversal of 21000385 is 58300012.

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 21000385 - 2¹³ = 20992193 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 299971 + ... + 300040.

It is an arithmetic number, because the mean of its divisors is an integer number (3600072).

Almost surely, 2^21000385 is an apocalyptic number.

It is an amenable number.

21000385 is a deficient number, since it is larger than the sum of its proper divisors (7800191).

21000385 is an equidigital number, since it uses as much as digits as its factorization.

21000385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 600023.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 21000385 is about 4582.6177017072. The cubic root of 21000385 is about 275.8941036370.

Adding to 21000385 its reverse (58300012), we get a palindrome (79300397).

The spelling of 21000385 in words is "twenty-one million, three hundred eighty-five", and thus it is an aban number.