21010481 has 4 divisors (see below), whose sum is σ = 21028212. Its totient is φ = 20992752.

The previous prime is 21010469. The next prime is 21010489. The reversal of 21010481 is 18401012.

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 16974400 + 4036081 = 4120^2 + 2009^2 .

It is a cyclic number.

It is not a de Polignac number, because 21010481 - 2¹⁴ = 20994097 is a prime.

It is a super-2 number, since 2×21010481² = 882880623702722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21010489) 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, 6950 + ... + 9503.

It is an arithmetic number, because the mean of its divisors is an integer number (5257053).

Almost surely, 2^21010481 is an apocalyptic number.

It is an amenable number.

21010481 is a deficient number, since it is larger than the sum of its proper divisors (17731).

21010481 is a wasteful number, since it uses less digits than its factorization.

21010481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17730.

The product of its (nonzero) digits is 64, while the sum is 17.

The square root of 21010481 is about 4583.7191231575. The cubic root of 21010481 is about 275.9383088682.

Adding to 21010481 its reverse (18401012), we get a palindrome (39411493).

The spelling of 21010481 in words is "twenty-one million, ten thousand, four hundred eighty-one".