21056045 has 8 divisors (see below), whose sum is σ = 25291896. Its totient is φ = 16828416.

The previous prime is 21056039. The next prime is 21056051. The reversal of 21056045 is 54065012.

It is an interprime number because it is at equal distance from previous prime (21056039) and next prime (21056051).

It can be written as a sum of positive squares in 4 ways, for example, as 88804 + 20967241 = 298^2 + 4579^2 .

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 21056045 - 2⁴ = 21056029 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21056045.

It is a congruent 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, 8909 + ... + 11021.

It is an arithmetic number, because the mean of its divisors is an integer number (3161487).

Almost surely, 2^21056045 is an apocalyptic number.

It is an amenable number.

21056045 is a deficient number, since it is larger than the sum of its proper divisors (4235851).

21056045 is a wasteful number, since it uses less digits than its factorization.

21056045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4111.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 21056045 is about 4588.6866312704. The cubic root of 21056045 is about 276.1376343923.

The spelling of 21056045 in words is "twenty-one million, fifty-six thousand, forty-five".