202121172 has 72 divisors (see below), whose sum is σ = 561087072. Its totient is φ = 60840000.

The previous prime is 202121137. The next prime is 202121189. The reversal of 202121172 is 271121202.

It is a happy number.

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 (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 60547 + ... + 63797.

It is an arithmetic number, because the mean of its divisors is an integer number (7792876).

Almost surely, 2^202121172 is an apocalyptic number.

202121172 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 202121172, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (280543536).

202121172 is an abundant number, since it is smaller than the sum of its proper divisors (358965900).

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

202121172 is a wasteful number, since it uses less digits than its factorization.

202121172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3429 (or 3424 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 202121172 is about 14216.9325805534. The cubic root of 202121172 is about 586.8637295688.

Adding to 202121172 its reverse (271121202), we get a palindrome (473242374).

The spelling of 202121172 in words is "two hundred two million, one hundred twenty-one thousand, one hundred seventy-two".