11978451999 has 6 divisors (see below), whose sum is σ = 17302208456. Its totient is φ = 7985634660.

The previous prime is 11978451973. The next prime is 11978452019. The reversal of 11978451999 is 99915487911.

11978451999 is a `hidden beast` number, since 1 + 1 + 97 + 8 + 451 + 9 + 99 = 666.

It is not a de Polignac number, because 11978451999 - 2⁷ = 11978451871 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 (11978451929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 665469547 + ... + 665469564.

Almost surely, 2^11978451999 is an apocalyptic number.

11978451999 is a deficient number, since it is larger than the sum of its proper divisors (5323756457).

11978451999 is a wasteful number, since it uses less digits than its factorization.

11978451999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1330939117 (or 1330939114 counting only the distinct ones).

The product of its digits is 7348320, while the sum is 63.

The spelling of 11978451999 in words is "eleven billion, nine hundred seventy-eight million, four hundred fifty-one thousand, nine hundred ninety-nine".