21030481 has 4 divisors (see below), whose sum is σ = 21755700. Its totient is φ = 20305264.

The previous prime is 21030469. The next prime is 21030551. The reversal of 21030481 is 18403012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9579025 + 11451456 = 3095^2 + 3384^2 .

It is a cyclic number.

It is not a de Polignac number, because 21030481 - 2¹¹ = 21028433 is a prime.

It is a super-2 number, since 2×21030481² = 884562262182722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21030181) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 362566 + ... + 362623.

It is an arithmetic number, because the mean of its divisors is an integer number (5438925).

Almost surely, 2^21030481 is an apocalyptic number.

It is an amenable number.

21030481 is a deficient number, since it is larger than the sum of its proper divisors (725219).

21030481 is an equidigital number, since it uses as much as digits as its factorization.

21030481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 725218.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 21030481 is about 4585.9002387754. The cubic root of 21030481 is about 276.0258368658.

Adding to 21030481 its reverse (18403012), we get a palindrome (39433493).

The spelling of 21030481 in words is "twenty-one million, thirty thousand, four hundred eighty-one".