20506172 has 6 divisors (see below), whose sum is σ = 35885808. Its totient is φ = 10253084.

The previous prime is 20506163. The next prime is 20506181. The reversal of 20506172 is 27160502.

It is an interprime number because it is at equal distance from previous prime (20506163) and next prime (20506181).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2563268 + ... + 2563275.

It is an arithmetic number, because the mean of its divisors is an integer number (5980968).

Almost surely, 2^20506172 is an apocalyptic number.

It is an amenable number.

20506172 is a deficient number, since it is larger than the sum of its proper divisors (15379636).

20506172 is a wasteful number, since it uses less digits than its factorization.

20506172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5126547 (or 5126545 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 20506172 is about 4528.3741011537. The cubic root of 20506172 is about 273.7126474059.

Adding to 20506172 its reverse (27160502), we get a palindrome (47666674).

The spelling of 20506172 in words is "twenty million, five hundred six thousand, one hundred seventy-two".