21048178 has 4 divisors (see below), whose sum is σ = 31572270. Its totient is φ = 10524088.

The previous prime is 21048173. The next prime is 21048221. The reversal of 21048178 is 87184012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 13935289 + 7112889 = 3733^2 + 2667^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21048173) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5262043 + ... + 5262046.

Almost surely, 2^21048178 is an apocalyptic number.

21048178 is a deficient number, since it is larger than the sum of its proper divisors (10524092).

21048178 is a wasteful number, since it uses less digits than its factorization.

21048178 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10524091.

The product of its (nonzero) digits is 3584, while the sum is 31.

The square root of 21048178 is about 4587.8293342277. The cubic root of 21048178 is about 276.1032397505.

The spelling of 21048178 in words is "twenty-one million, forty-eight thousand, one hundred seventy-eight".