20115211555 has 16 divisors (see below), whose sum is σ = 25670645280. Its totient is φ = 15088038912.

The previous prime is 20115211547. The next prime is 20115211561. The reversal of 20115211555 is 55511251102.

It is a cyclic number.

It is not a de Polignac number, because 20115211555 - 2³ = 20115211547 is a prime.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 1082224 + ... + 1100653.

It is an arithmetic number, because the mean of its divisors is an integer number (1604415330).

Almost surely, 2^20115211555 is an apocalyptic number.

20115211555 is a deficient number, since it is larger than the sum of its proper divisors (5555433725).

20115211555 is a wasteful number, since it uses less digits than its factorization.

20115211555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2182998.

The product of its (nonzero) digits is 2500, while the sum is 28.

Adding to 20115211555 its reverse (55511251102), we get a palindrome (75626462657).

The spelling of 20115211555 in words is "twenty billion, one hundred fifteen million, two hundred eleven thousand, five hundred fifty-five".