21333385 has 16 divisors (see below), whose sum is σ = 27216000. Its totient is φ = 15997696.

The previous prime is 21333353. The next prime is 21333413. The reversal of 21333385 is 58333312.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21333385 - 2⁵ = 21333353 is a prime.

It is a super-2 number, since 2×21333385² = 910226631116450, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35316 + ... + 35914.

It is an arithmetic number, because the mean of its divisors is an integer number (1701000).

Almost surely, 2^21333385 is an apocalyptic number.

It is an amenable number.

21333385 is a deficient number, since it is larger than the sum of its proper divisors (5882615).

21333385 is a wasteful number, since it uses less digits than its factorization.

21333385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1040.

The product of its digits is 6480, while the sum is 28.

The square root of 21333385 is about 4618.8077465944. The cubic root of 21333385 is about 277.3447336380.

Adding to 21333385 its reverse (58333312), we get a palindrome (79666697).

The spelling of 21333385 in words is "twenty-one million, three hundred thirty-three thousand, three hundred eighty-five".