21062709 has 12 divisors (see below), whose sum is σ = 30525196. Its totient is φ = 13995072.

The previous prime is 21062707. The next prime is 21062719. The reversal of 21062709 is 90726012.

It can be written as a sum of positive squares in 2 ways, for example, as 9180900 + 11881809 = 3030^2 + 3447^2 .

It is not a de Polignac number, because 21062709 - 2¹ = 21062707 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 (21062707) 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, 922 + ... + 6555.

Almost surely, 2^21062709 is an apocalyptic number.

It is an amenable number.

21062709 is a deficient number, since it is larger than the sum of its proper divisors (9462487).

21062709 is a wasteful number, since it uses less digits than its factorization.

21062709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7796 (or 7793 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 21062709 is about 4589.4127075259. The cubic root of 21062709 is about 276.1667627985.

The spelling of 21062709 in words is "twenty-one million, sixty-two thousand, seven hundred nine".