1213638399 has 24 divisors (see below), whose sum is σ = 1766802960. Its totient is φ = 802764288.

The previous prime is 1213638389. The next prime is 1213638403. The reversal of 1213638399 is 9938363121.

1213638399 is a `hidden beast` number, since 1 + 2 + 1 + 3 + 638 + 3 + 9 + 9 = 666.

It is not a de Polignac number, because 1213638399 - 2¹³ = 1213630207 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213638389) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 714319 + ... + 716015.

It is an arithmetic number, because the mean of its divisors is an integer number (73616790).

Almost surely, 2^1213638399 is an apocalyptic number.

1213638399 is a deficient number, since it is larger than the sum of its proper divisors (553164561).

1213638399 is a wasteful number, since it uses less digits than its factorization.

1213638399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2279 (or 2276 counting only the distinct ones).

The product of its digits is 209952, while the sum is 45.

The square root of 1213638399 is about 34837.3133148927. The cubic root of 1213638399 is about 1066.6692358120.

The spelling of 1213638399 in words is "one billion, two hundred thirteen million, six hundred thirty-eight thousand, three hundred ninety-nine".