20645172 has 48 divisors (see below), whose sum is σ = 56347200. Its totient is φ = 6518880.

The previous prime is 20645161. The next prime is 20645197. The reversal of 20645172 is 27154602.

20645172 is a `hidden beast` number, since 2 + 0 + 645 + 17 + 2 = 666.

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

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 2979 + ... + 7082.

It is an arithmetic number, because the mean of its divisors is an integer number (1173900).

Almost surely, 2^20645172 is an apocalyptic number.

It is an amenable number.

20645172 is an abundant number, since it is smaller than the sum of its proper divisors (35702028).

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

20645172 is a wasteful number, since it uses less digits than its factorization.

20645172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10093 (or 10085 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 20645172 is about 4543.6958524972. The cubic root of 20645172 is about 274.3297041611.

Adding to 20645172 its reverse (27154602), we get a palindrome (47799774).

The spelling of 20645172 in words is "twenty million, six hundred forty-five thousand, one hundred seventy-two".