20531211155 has 16 divisors (see below), whose sum is σ = 30323020224. Its totient is φ = 12995579520.

The previous prime is 20531211143. The next prime is 20531211157. The reversal of 20531211155 is 55111213502.

It is not a de Polignac number, because 20531211155 - 2⁴ = 20531211139 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20531211157) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22561316 + ... + 22562225.

It is an arithmetic number, because the mean of its divisors is an integer number (1895188764).

Almost surely, 2^20531211155 is an apocalyptic number.

20531211155 is a deficient number, since it is larger than the sum of its proper divisors (9791809069).

20531211155 is a wasteful number, since it uses less digits than its factorization.

20531211155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45123566.

The product of its (nonzero) digits is 1500, while the sum is 26.

Adding to 20531211155 its reverse (55111213502), we get a palindrome (75642424657).

The spelling of 20531211155 in words is "twenty billion, five hundred thirty-one million, two hundred eleven thousand, one hundred fifty-five".