21024145 has 8 divisors (see below), whose sum is σ = 25298856. Its totient is φ = 16772736.

The previous prime is 21024137. The next prime is 21024173. The reversal of 21024145 is 54142012.

It can be written as a sum of positive squares in 4 ways, for example, as 944784 + 20079361 = 972^2 + 4481^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21024145 - 2³ = 21024137 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3772 + ... + 7501.

It is an arithmetic number, because the mean of its divisors is an integer number (3162357).

Almost surely, 2^21024145 is an apocalyptic number.

It is an amenable number.

21024145 is a deficient number, since it is larger than the sum of its proper divisors (4274711).

21024145 is a wasteful number, since it uses less digits than its factorization.

21024145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11651.

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 21024145 is about 4585.2093736273. The cubic root of 21024145 is about 275.9981140038.

Adding to 21024145 its reverse (54142012), we get a palindrome (75166157).

The spelling of 21024145 in words is "twenty-one million, twenty-four thousand, one hundred forty-five".