20938213 has 2 divisors, whose sum is σ = 20938214. Its totient is φ = 20938212.

The previous prime is 20938207. The next prime is 20938231. The reversal of 20938213 is 31283902.

Together with next prime (20938231) 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., 13198689 + 7739524 = 3633^2 + 2782^2 .

It is a cyclic number.

It is not a de Polignac number, because 20938213 - 2²¹ = 18841061 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20938283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10469106 + 10469107.

It is an arithmetic number, because the mean of its divisors is an integer number (10469107).

Almost surely, 2^20938213 is an apocalyptic number.

It is an amenable number.

20938213 is a deficient number, since it is larger than the sum of its proper divisors (1).

20938213 is an equidigital number, since it uses as much as digits as its factorization.

20938213 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 20938213 is about 4575.8292144703. The cubic root of 20938213 is about 275.6215714391.

The spelling of 20938213 in words is "twenty million, nine hundred thirty-eight thousand, two hundred thirteen".