21802145 has 8 divisors (see below), whose sum is σ = 27006720. Its totient is φ = 16878960.

The previous prime is 21802141. The next prime is 21802159. The reversal of 21802145 is 54120812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21802145 - 2² = 21802141 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21802145.

It is not an unprimeable number, because it can be changed into a prime (21802141) 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 in 7 ways as a sum of consecutive naturals, for example, 70175 + ... + 70484.

It is an arithmetic number, because the mean of its divisors is an integer number (3375840).

Almost surely, 2^21802145 is an apocalyptic number.

It is an amenable number.

21802145 is a deficient number, since it is larger than the sum of its proper divisors (5204575).

21802145 is a wasteful number, since it uses less digits than its factorization.

21802145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140695.

The product of its (nonzero) digits is 640, while the sum is 23.

The square root of 21802145 is about 4669.2767105838. The cubic root of 21802145 is about 279.3614060653.

Adding to 21802145 its reverse (54120812), we get a palindrome (75922957).

The spelling of 21802145 in words is "twenty-one million, eight hundred two thousand, one hundred forty-five".