20645105555 has 16 divisors (see below), whose sum is σ = 26401296384. Its totient is φ = 15461862240.

The previous prime is 20645105489. The next prime is 20645105581. The reversal of 20645105555 is 55550154602.

It is not a de Polignac number, because 20645105555 - 2¹² = 20645101459 is a prime.

It is a super-3 number, since 3×20645105555³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

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, 1904411 + ... + 1915220.

It is an arithmetic number, because the mean of its divisors is an integer number (1650081024).

Almost surely, 2^20645105555 is an apocalyptic number.

20645105555 is a deficient number, since it is larger than the sum of its proper divisors (5756190829).

20645105555 is a wasteful number, since it uses less digits than its factorization.

20645105555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3819706.

The product of its (nonzero) digits is 150000, while the sum is 38.

The spelling of 20645105555 in words is "twenty billion, six hundred forty-five million, one hundred five thousand, five hundred fifty-five".