20420172 has 36 divisors (see below), whose sum is σ = 51902760. Its totient is φ = 6769152.

The previous prime is 20420167. The next prime is 20420207. The reversal of 20420172 is 27102402.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

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 in 11 ways as a sum of consecutive naturals, for example, 5479 + ... + 8417.

Almost surely, 2^20420172 is an apocalyptic number.

It is an amenable number.

20420172 is an abundant number, since it is smaller than the sum of its proper divisors (31482588).

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

20420172 is a wasteful number, since it uses less digits than its factorization.

20420172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3142 (or 3137 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 18.

The square root of 20420172 is about 4518.8684424311. The cubic root of 20420172 is about 273.3294738037.

Adding to 20420172 its reverse (27102402), we get a palindrome (47522574).

The spelling of 20420172 in words is "twenty million, four hundred twenty thousand, one hundred seventy-two".