21081067 has 4 divisors (see below), whose sum is σ = 24092656. Its totient is φ = 18069480.

The previous prime is 21081061. The next prime is 21081101. The reversal of 21081067 is 76018012.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21081067 is a prime.

It is a super-2 number, since 2×21081067² = 888822771716978, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21081061) 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, 1505784 + ... + 1505797.

It is an arithmetic number, because the mean of its divisors is an integer number (6023164).

Almost surely, 2^21081067 is an apocalyptic number.

21081067 is a deficient number, since it is larger than the sum of its proper divisors (3011589).

21081067 is an equidigital number, since it uses as much as digits as its factorization.

21081067 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3011588.

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 21081067 is about 4591.4123099543. The cubic root of 21081067 is about 276.2469740255.

Adding to 21081067 its reverse (76018012), we get a palindrome (97099079).

The spelling of 21081067 in words is "twenty-one million, eighty-one thousand, sixty-seven".