21001041 has 12 divisors (see below), whose sum is σ = 30481360. Its totient is φ = 13933080.

The previous prime is 21001037. The next prime is 21001049. The reversal of 21001041 is 14010012.

It is a happy number.

It is not a de Polignac number, because 21001041 - 2² = 21001037 is a prime.

It is a super-3 number, since 3×21001041³ (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21001049) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3631 + ... + 7428.

Almost surely, 2^21001041 is an apocalyptic number.

It is an amenable number.

21001041 is a deficient number, since it is larger than the sum of its proper divisors (9480319).

21001041 is a wasteful number, since it uses less digits than its factorization.

21001041 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11276 (or 11273 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 21001041 is about 4582.6892759601. The cubic root of 21001041 is about 275.8969763565.

Adding to 21001041 its reverse (14010012), we get a palindrome (35011053).

The spelling of 21001041 in words is "twenty-one million, one thousand, forty-one".