21702393 has 12 divisors (see below), whose sum is σ = 31425940. Its totient is φ = 14432256.

The previous prime is 21702379. The next prime is 21702403. The reversal of 21702393 is 39320712.

It can be written as a sum of positive squares in 2 ways, for example, as 3143529 + 18558864 = 1773^2 + 4308^2 .

It is not a de Polignac number, because 21702393 - 2⁵ = 21702361 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21702323) 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, 1113 + ... + 6681.

Almost surely, 2^21702393 is an apocalyptic number.

It is an amenable number.

21702393 is a deficient number, since it is larger than the sum of its proper divisors (9723547).

21702393 is a wasteful number, since it uses less digits than its factorization.

21702393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6008 (or 6005 counting only the distinct ones).

The product of its (nonzero) digits is 2268, while the sum is 27.

The square root of 21702393 is about 4658.5827243916. The cubic root of 21702393 is about 278.9346977856.

The spelling of 21702393 in words is "twenty-one million, seven hundred two thousand, three hundred ninety-three".