21021027 has 32 divisors (see below), whose sum is σ = 31337280. Its totient is φ = 12472320.

The previous prime is 21021001. The next prime is 21021043. The reversal of 21021027 is 72012012.

It is not a de Polignac number, because 21021027 - 2⁶ = 21020963 is a prime.

It is a super-2 number, since 2×21021027² = 883767152269458, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21020997 and 21021015.

It is not an unprimeable number, because it can be changed into a prime (21021047) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 90103 + ... + 90335.

It is an arithmetic number, because the mean of its divisors is an integer number (979290).

Almost surely, 2^21021027 is an apocalyptic number.

21021027 is a deficient number, since it is larger than the sum of its proper divisors (10316253).

21021027 is a wasteful number, since it uses less digits than its factorization.

21021027 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 343.

The product of its (nonzero) digits is 56, while the sum is 15.

The square root of 21021027 is about 4584.8693547363. The cubic root of 21021027 is about 275.9844693004.

Adding to 21021027 its reverse (72012012), we get a palindrome (93033039).

The spelling of 21021027 in words is "twenty-one million, twenty-one thousand, twenty-seven".