21039093 has 6 divisors (see below), whose sum is σ = 30389814. Its totient is φ = 14026056.

The previous prime is 21039091. The next prime is 21039097. The reversal of 21039093 is 39093012.

It can be written as a sum of positive squares in only one way, i.e., 12236004 + 8803089 = 3498^2 + 2967^2 .

It is not a de Polignac number, because 21039093 - 2¹ = 21039091 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21039091) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1168830 + ... + 1168847.

It is an arithmetic number, because the mean of its divisors is an integer number (5064969).

Almost surely, 2^21039093 is an apocalyptic number.

It is an amenable number.

21039093 is a deficient number, since it is larger than the sum of its proper divisors (9350721).

21039093 is a wasteful number, since it uses less digits than its factorization.

21039093 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2337683 (or 2337680 counting only the distinct ones).

The product of its (nonzero) digits is 1458, while the sum is 27.

The square root of 21039093 is about 4586.8391077081. The cubic root of 21039093 is about 276.0635093295.

The spelling of 21039093 in words is "twenty-one million, thirty-nine thousand, ninety-three".