21026445 has 48 divisors (see below), whose sum is σ = 38843712. Its totient is φ = 9630720.

The previous prime is 21026443. The next prime is 21026477. The reversal of 21026445 is 54462012.

It is not a de Polignac number, because 21026445 - 2¹ = 21026443 is a prime.

It is a super-2 number, since 2×21026445² = 884222778676050, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21026443) 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 47 ways as a sum of consecutive naturals, for example, 59389 + ... + 59741.

It is an arithmetic number, because the mean of its divisors is an integer number (809244).

Almost surely, 2^21026445 is an apocalyptic number.

It is an amenable number.

21026445 is a deficient number, since it is larger than the sum of its proper divisors (17817267).

21026445 is a wasteful number, since it uses less digits than its factorization.

21026445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 410 (or 391 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 21026445 is about 4585.4601731996. The cubic root of 21026445 is about 276.0081781866.

Adding to 21026445 its reverse (54462012), we get a palindrome (75488457).

The spelling of 21026445 in words is "twenty-one million, twenty-six thousand, four hundred forty-five".