21012727 has 6 divisors (see below), whose sum is σ = 22177248. Its totient is φ = 19906452.

The previous prime is 21012701. The next prime is 21012737. The reversal of 21012727 is 72721012.

It is not a de Polignac number, because 21012727 - 2⁷ = 21012599 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21012698 and 21012707.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 28743 + ... + 29464.

It is an arithmetic number, because the mean of its divisors is an integer number (3696208).

Almost surely, 2^21012727 is an apocalyptic number.

21012727 is a deficient number, since it is larger than the sum of its proper divisors (1164521).

21012727 is an equidigital number, since it uses as much as digits as its factorization.

21012727 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58245 (or 58226 counting only the distinct ones).

The product of its (nonzero) digits is 392, while the sum is 22.

The square root of 21012727 is about 4583.9641141702. The cubic root of 21012727 is about 275.9481410302.

Adding to 21012727 its reverse (72721012), we get a palindrome (93733739).

The spelling of 21012727 in words is "twenty-one million, twelve thousand, seven hundred twenty-seven".