20381790645 has 80 divisors (see below), whose sum is σ = 37774099440. Its totient is φ = 10506931200.

The previous prime is 20381790623. The next prime is 20381790647. The reversal of 20381790645 is 54609718302.

It can be written as a sum of positive squares in 8 ways, for example, as 178863876 + 20202926769 = 13374^2 + 142137^2 .

It is not a de Polignac number, because 20381790645 - 2⁶ = 20381790581 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 20381790645.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20381790647) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 1804315 + ... + 1815575.

It is an arithmetic number, because the mean of its divisors is an integer number (472176243).

It is a 2-persistent number, because it is pandigital, and so is 2⋅20381790645 = 40763581290, but 3⋅20381790645 = 61145371935 is not.

Almost surely, 2^20381790645 is an apocalyptic number.

It is an amenable number.

20381790645 is a deficient number, since it is larger than the sum of its proper divisors (17392308795).

20381790645 is a wasteful number, since it uses less digits than its factorization.

20381790645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11428 (or 11419 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The spelling of 20381790645 in words is "twenty billion, three hundred eighty-one million, seven hundred ninety thousand, six hundred forty-five".