19871213 has 2 divisors, whose sum is σ = 19871214. Its totient is φ = 19871212.

The previous prime is 19871197. The next prime is 19871219. The reversal of 19871213 is 31217891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10738729 + 9132484 = 3277^2 + 3022^2 .

It is a cyclic number.

It is not a de Polignac number, because 19871213 - 2⁴ = 19871197 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19871213.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19871219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9935606 + 9935607.

It is an arithmetic number, because the mean of its divisors is an integer number (9935607).

Almost surely, 2^19871213 is an apocalyptic number.

It is an amenable number.

19871213 is a deficient number, since it is larger than the sum of its proper divisors (1).

19871213 is an equidigital number, since it uses as much as digits as its factorization.

19871213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 32.

The square root of 19871213 is about 4457.7138759683. The cubic root of 19871213 is about 270.8578703976.

The spelling of 19871213 in words is "nineteen million, eight hundred seventy-one thousand, two hundred thirteen".