20105555 has 16 divisors (see below), whose sum is σ = 25094880. Its totient is φ = 15445248.

The previous prime is 20105551. The next prime is 20105573. The reversal of 20105555 is 55550102.

It is a cyclic number.

It is not a de Polignac number, because 20105555 - 2² = 20105551 is a prime.

20105555 is a modest number, since divided by 5555 gives 2010 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 20105555.

It is not an unprimeable number, because it can be changed into a prime (20105551) 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, 45164 + ... + 45606.

It is an arithmetic number, because the mean of its divisors is an integer number (1568430).

Almost surely, 2^20105555 is an apocalyptic number.

20105555 is a deficient number, since it is larger than the sum of its proper divisors (4989325).

20105555 is a wasteful number, since it uses less digits than its factorization.

20105555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 790.

The product of its (nonzero) digits is 1250, while the sum is 23.

The square root of 20105555 is about 4483.9218325033. The cubic root of 20105555 is about 271.9184579318.

Adding to 20105555 its reverse (55550102), we get a palindrome (75655657).

The spelling of 20105555 in words is "twenty million, one hundred five thousand, five hundred fifty-five".