21152145 has 16 divisors (see below), whose sum is σ = 38678400. Its totient is φ = 9669504.

The previous prime is 21152143. The next prime is 21152207. The reversal of 21152145 is 54125112.

It is not a de Polignac number, because 21152145 - 2¹ = 21152143 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (21152143) 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, 100620 + ... + 100829.

It is an arithmetic number, because the mean of its divisors is an integer number (2417400).

Almost surely, 2^21152145 is an apocalyptic number.

It is an amenable number.

21152145 is a deficient number, since it is larger than the sum of its proper divisors (17526255).

21152145 is a wasteful number, since it uses less digits than its factorization.

21152145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 201464.

The product of its digits is 400, while the sum is 21.

The square root of 21152145 is about 4599.1461164003. The cubic root of 21152145 is about 276.5570952054.

Adding to 21152145 its reverse (54125112), we get a palindrome (75277257).

The spelling of 21152145 in words is "twenty-one million, one hundred fifty-two thousand, one hundred forty-five".