42172220 has 12 divisors (see below), whose sum is σ = 88561704. Its totient is φ = 16868880.

The previous prime is 42172219. The next prime is 42172297. The reversal of 42172220 is 2227124.

It is a happy number.

It is a super-2 number, since 2×42172220² = 3556992279456800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 2108611 = 42172220 / (4 + 2 + 1 + 7 + 2 + 2 + 2 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 42172192 and 42172201.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1054286 + ... + 1054325.

It is an arithmetic number, because the mean of its divisors is an integer number (7380142).

Almost surely, 2^42172220 is an apocalyptic number.

It is an amenable number.

42172220 is an abundant number, since it is smaller than the sum of its proper divisors (46389484).

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

42172220 is a wasteful number, since it uses less digits than its factorization.

42172220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2108620 (or 2108618 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 20.

The square root of 42172220 is about 6494.0141669079. The cubic root of 42172220 is about 348.0771287184.

Adding to 42172220 its reverse (2227124), we get a palindrome (44399344).

The spelling of 42172220 in words is "forty-two million, one hundred seventy-two thousand, two hundred twenty".