21035709 has 12 divisors (see below), whose sum is σ = 30430816. Its totient is φ = 14002632.

The previous prime is 21035699. The next prime is 21035737. The reversal of 21035709 is 90753012.

It is not a de Polignac number, because 21035709 - 2⁹ = 21035197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21035779) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6624 + ... + 9270.

Almost surely, 2^21035709 is an apocalyptic number.

It is an amenable number.

21035709 is a deficient number, since it is larger than the sum of its proper divisors (9395107).

21035709 is a wasteful number, since it uses less digits than its factorization.

21035709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3536 (or 3533 counting only the distinct ones).

The product of its (nonzero) digits is 1890, while the sum is 27.

The square root of 21035709 is about 4586.4702113935. The cubic root of 21035709 is about 276.0487075348.

The spelling of 21035709 in words is "twenty-one million, thirty-five thousand, seven hundred nine".