20402172 has 48 divisors (see below), whose sum is σ = 60453120. Its totient is φ = 5828976.

The previous prime is 20402153. The next prime is 20402189. The reversal of 20402172 is 27120402.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12738 + ... + 14249.

It is an arithmetic number, because the mean of its divisors is an integer number (1259440).

Almost surely, 2^20402172 is an apocalyptic number.

It is an amenable number.

20402172 is an abundant number, since it is smaller than the sum of its proper divisors (40050948).

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

20402172 is a wasteful number, since it uses less digits than its factorization.

20402172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27007 (or 26999 counting only the distinct ones).

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

The square root of 20402172 is about 4516.8763542962. The cubic root of 20402172 is about 273.2491385867.

Adding to 20402172 its reverse (27120402), we get a palindrome (47522574).

The spelling of 20402172 in words is "twenty million, four hundred two thousand, one hundred seventy-two".