21148289 has 16 divisors (see below), whose sum is σ = 23023440. Its totient is φ = 19353600.

The previous prime is 21148277. The next prime is 21148297. The reversal of 21148289 is 98284112.

It can be written as a sum of positive squares in 8 ways, for example, as 970225 + 20178064 = 985^2 + 4492^2 .

It is a cyclic number.

It is not a de Polignac number, because 21148289 - 2⁸ = 21148033 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21148249) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 187097 + ... + 187209.

It is an arithmetic number, because the mean of its divisors is an integer number (1438965).

Almost surely, 2^21148289 is an apocalyptic number.

It is an amenable number.

21148289 is a deficient number, since it is larger than the sum of its proper divisors (1875151).

21148289 is a wasteful number, since it uses less digits than its factorization.

21148289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 340.

The product of its digits is 9216, while the sum is 35.

The square root of 21148289 is about 4598.7268890422. The cubic root of 21148289 is about 276.5402888884.

The spelling of 21148289 in words is "twenty-one million, one hundred forty-eight thousand, two hundred eighty-nine".