20645131311 has 32 divisors (see below), whose sum is σ = 35698452480. Its totient is φ = 11546208288.

The previous prime is 20645131289. The next prime is 20645131333. The reversal of 20645131311 is 11313154602.

It is a happy number.

20645131311 is a `hidden beast` number, since 2 + 0 + 645 + 1 + 3 + 1 + 3 + 11 = 666.

It is an interprime number because it is at equal distance from previous prime (20645131289) and next prime (20645131333).

It is not a de Polignac number, because 20645131311 - 2⁹ = 20645130799 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20645131391) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 1153176 + ... + 1170941.

It is an arithmetic number, because the mean of its divisors is an integer number (1115576640).

Almost surely, 2^20645131311 is an apocalyptic number.

20645131311 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

20645131311 is a deficient number, since it is larger than the sum of its proper divisors (15053321169).

20645131311 is a wasteful number, since it uses less digits than its factorization.

20645131311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2324180 (or 2324174 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

Adding to 20645131311 its reverse (11313154602), we get a palindrome (31958285913).

The spelling of 20645131311 in words is "twenty billion, six hundred forty-five million, one hundred thirty-one thousand, three hundred eleven".