21021069 has 32 divisors (see below), whose sum is σ = 30643200. Its totient is φ = 12787200.

The previous prime is 21021067. The next prime is 21021083. The reversal of 21021069 is 96012012.

It is not a de Polignac number, because 21021069 - 2¹ = 21021067 is a prime.

It is a super-2 number, since 2×21021069² = 883770683805522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021067) 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, 141007 + ... + 141155.

It is an arithmetic number, because the mean of its divisors is an integer number (957600).

Almost surely, 2^21021069 is an apocalyptic number.

It is an amenable number.

21021069 is a deficient number, since it is larger than the sum of its proper divisors (9622131).

21021069 is a wasteful number, since it uses less digits than its factorization.

21021069 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261.

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 21021069 is about 4584.8739350172. The cubic root of 21021069 is about 275.9846531059.

The spelling of 21021069 in words is "twenty-one million, twenty-one thousand, sixty-nine".