22170728 has 8 divisors (see below), whose sum is σ = 41570130. Its totient is φ = 11085360.

The previous prime is 22170727. The next prime is 22170767. The reversal of 22170728 is 82707122.

It can be written as a sum of positive squares in only one way, i.e., 14002564 + 8168164 = 3742^2 + 2858^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 22170728.

It is not an unprimeable number, because it can be changed into a prime (22170727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1385663 + ... + 1385678.

Almost surely, 2^22170728 is an apocalyptic number.

It is an amenable number.

22170728 is a deficient number, since it is larger than the sum of its proper divisors (19399402).

22170728 is a wasteful number, since it uses less digits than its factorization.

22170728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2771347 (or 2771343 counting only the distinct ones).

The product of its (nonzero) digits is 3136, while the sum is 29.

The square root of 22170728 is about 4708.5802531124. The cubic root of 22170728 is about 280.9268942686.

The spelling of 22170728 in words is "twenty-two million, one hundred seventy thousand, seven hundred twenty-eight".