20645316 has 18 divisors (see below), whose sum is σ = 52186862. Its totient is φ = 6881760.

The previous prime is 20645311. The next prime is 20645321. The reversal of 20645316 is 61354602.

20645316 is a `hidden beast` number, since 2 + 0 + 645 + 3 + 16 = 666.

It is an interprime number because it is at equal distance from previous prime (20645311) and next prime (20645321).

It can be written as a sum of positive squares in only one way, i.e., 16842816 + 3802500 = 4104^2 + 1950^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a self number, because there is not a number n which added to its sum of digits gives 20645316.

It is not an unprimeable number, because it can be changed into a prime (20645311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 286705 + ... + 286776.

Almost surely, 2^20645316 is an apocalyptic number.

It is an amenable number.

20645316 is an abundant number, since it is smaller than the sum of its proper divisors (31541546).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20645316 is a wasteful number, since it uses less digits than its factorization.

20645316 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 573491 (or 573486 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 20645316 is about 4543.7116986006. The cubic root of 20645316 is about 274.3303419758.

Adding to 20645316 its reverse (61354602), we get a palindrome (81999918).

The spelling of 20645316 in words is "twenty million, six hundred forty-five thousand, three hundred sixteen".