20947613 has 2 divisors, whose sum is σ = 20947614. Its totient is φ = 20947612.

The previous prime is 20947609. The next prime is 20947631. The reversal of 20947613 is 31674902.

Together with next prime (20947631) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19377604 + 1570009 = 4402^2 + 1253^2 .

It is a cyclic number.

It is not a de Polignac number, because 20947613 - 2² = 20947609 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20947613.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20943613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10473806 + 10473807.

It is an arithmetic number, because the mean of its divisors is an integer number (10473807).

Almost surely, 2^20947613 is an apocalyptic number.

It is an amenable number.

20947613 is a deficient number, since it is larger than the sum of its proper divisors (1).

20947613 is an equidigital number, since it uses as much as digits as its factorization.

20947613 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9072, while the sum is 32.

The square root of 20947613 is about 4576.8562354525. The cubic root of 20947613 is about 275.6628111118.

The spelling of 20947613 in words is "twenty million, nine hundred forty-seven thousand, six hundred thirteen".