20715389 has 4 divisors (see below), whose sum is σ = 20965056. Its totient is φ = 20465724.

The previous prime is 20715349. The next prime is 20715407. The reversal of 20715389 is 98351702.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20715389 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 (20715319) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 124709 + ... + 124874.

It is an arithmetic number, because the mean of its divisors is an integer number (5241264).

Almost surely, 2^20715389 is an apocalyptic number.

It is an amenable number.

20715389 is a deficient number, since it is larger than the sum of its proper divisors (249667).

20715389 is an equidigital number, since it uses as much as digits as its factorization.

20715389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 249666.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 20715389 is about 4551.4161532429. The cubic root of 20715389 is about 274.6403629399.

The spelling of 20715389 in words is "twenty million, seven hundred fifteen thousand, three hundred eighty-nine".