155999999999 has 4 divisors (see below), whose sum is σ = 156418230936. Its totient is φ = 155581769064.

The previous prime is 155999999971. The next prime is 156000000007. The reversal of 155999999999 is 999999999551.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 155999999999 - 2²⁸ = 155731564543 is a prime.

It is a Duffinian number.

155999999999 is a modest number, since divided by 999999 gives 155999 as remainder.

It is a plaindrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155999999899) 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, 209114909 + ... + 209115654.

It is an arithmetic number, because the mean of its divisors is an integer number (39104557734).

Almost surely, 2^155999999999 is an apocalyptic number.

155999999999 is a deficient number, since it is larger than the sum of its proper divisors (418230937).

155999999999 is an equidigital number, since it uses as much as digits as its factorization.

155999999999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 418230936.

The product of its digits is 9685512225, while the sum is 92.

The spelling of 155999999999 in words is "one hundred fifty-five billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred ninety-nine".