21029385 has 16 divisors (see below), whose sum is σ = 36235584. Its totient is φ = 10352832.

The previous prime is 21029369. The next prime is 21029387. The reversal of 21029385 is 58392012.

It is a happy number.

It is not a de Polignac number, because 21029385 - 2⁴ = 21029369 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21029387) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53727 + ... + 54116.

It is an arithmetic number, because the mean of its divisors is an integer number (2264724).

Almost surely, 2^21029385 is an apocalyptic number.

It is an amenable number.

21029385 is a deficient number, since it is larger than the sum of its proper divisors (15206199).

21029385 is a wasteful number, since it uses less digits than its factorization.

21029385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107864.

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 21029385 is about 4585.7807405065. The cubic root of 21029385 is about 276.0210417690.

The spelling of 21029385 in words is "twenty-one million, twenty-nine thousand, three hundred eighty-five".