19957213 has 4 divisors (see below), whose sum is σ = 19968988. Its totient is φ = 19945440.

The previous prime is 19957207. The next prime is 19957219. The reversal of 19957213 is 31275991.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 31275991 = 2203 ⋅14197.

It is an interprime number because it is at equal distance from previous prime (19957207) and next prime (19957219).

It can be written as a sum of positive squares in 2 ways, for example, as 4251844 + 15705369 = 2062^2 + 3963^2 .

It is a cyclic number.

It is not a de Polignac number, because 19957213 - 2¹⁷ = 19826141 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 (19957219) 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, 2808 + ... + 6913.

It is an arithmetic number, because the mean of its divisors is an integer number (4992247).

Almost surely, 2^19957213 is an apocalyptic number.

It is an amenable number.

19957213 is a deficient number, since it is larger than the sum of its proper divisors (11775).

19957213 is an equidigital number, since it uses as much as digits as its factorization.

19957213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11774.

The product of its digits is 17010, while the sum is 37.

The square root of 19957213 is about 4467.3496617122. The cubic root of 19957213 is about 271.2480538132.

The spelling of 19957213 in words is "nineteen million, nine hundred fifty-seven thousand, two hundred thirteen".