11997639 has 24 divisors (see below), whose sum is σ = 18192720. Its totient is φ = 7900416.

The previous prime is 11997637. The next prime is 11997647. The reversal of 11997639 is 93679911.

11997639 is a `hidden beast` number, since 1 + 1 + 9 + 9 + 7 + 639 = 666.

It is not a de Polignac number, because 11997639 - 2¹ = 11997637 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 11997594 and 11997603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11997637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23317 + ... + 23825.

It is an arithmetic number, because the mean of its divisors is an integer number (758030).

Almost surely, 2^11997639 is an apocalyptic number.

11997639 is a deficient number, since it is larger than the sum of its proper divisors (6195081).

11997639 is an frugal number, since it uses more digits than its factorization.

11997639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 621 (or 609 counting only the distinct ones).

The product of its digits is 91854, while the sum is 45.

The square root of 11997639 is about 3463.7608173776. The cubic root of 11997639 is about 228.9278326907.

The spelling of 11997639 in words is "eleven million, nine hundred ninety-seven thousand, six hundred thirty-nine".