21030571 has 4 divisors (see below), whose sum is σ = 21146944. Its totient is φ = 20914200.

The previous prime is 21030557. The next prime is 21030589. The reversal of 21030571 is 17503012.

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

It is a cyclic number.

It is not a de Polignac number, because 21030571 - 2¹⁷ = 20899499 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21030551) 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, 57915 + ... + 58276.

It is an arithmetic number, because the mean of its divisors is an integer number (5286736).

Almost surely, 2^21030571 is an apocalyptic number.

21030571 is a deficient number, since it is larger than the sum of its proper divisors (116373).

21030571 is a wasteful number, since it uses less digits than its factorization.

21030571 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116372.

The product of its (nonzero) digits is 210, while the sum is 19.

The square root of 21030571 is about 4585.9100514511. The cubic root of 21030571 is about 276.0262306163.

Adding to 21030571 its reverse (17503012), we get a palindrome (38533583).

The spelling of 21030571 in words is "twenty-one million, thirty thousand, five hundred seventy-one".