20231555 has 4 divisors (see below), whose sum is σ = 24277872. Its totient is φ = 16185240.

The previous prime is 20231551. The next prime is 20231557. The reversal of 20231555 is 55513202.

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

It is not a de Polignac number, because 20231555 - 2² = 20231551 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20231555.

It is not an unprimeable number, because it can be changed into a prime (20231551) 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, 2023151 + ... + 2023160.

It is an arithmetic number, because the mean of its divisors is an integer number (6069468).

Almost surely, 2^20231555 is an apocalyptic number.

20231555 is a deficient number, since it is larger than the sum of its proper divisors (4046317).

20231555 is an equidigital number, since it uses as much as digits as its factorization.

20231555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4046316.

The product of its (nonzero) digits is 1500, while the sum is 23.

The square root of 20231555 is about 4497.9500886515. The cubic root of 20231555 is about 272.4853062806.

Adding to 20231555 its reverse (55513202), we get a palindrome (75744757).

The spelling of 20231555 in words is "twenty million, two hundred thirty-one thousand, five hundred fifty-five".