21002769 has 12 divisors (see below), whose sum is σ = 32122116. Its totient is φ = 13178112.

The previous prime is 21002767. The next prime is 21002777. The reversal of 21002769 is 96720012.

It can be written as a sum of positive squares in 2 ways, for example, as 18378369 + 2624400 = 4287^2 + 1620^2 .

It is not a de Polignac number, because 21002769 - 2¹ = 21002767 is a prime.

It is a super-2 number, since 2×21002769² = 882232611334722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21002767) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 68484 + ... + 68789.

It is an arithmetic number, because the mean of its divisors is an integer number (2676843).

Almost surely, 2^21002769 is an apocalyptic number.

It is an amenable number.

21002769 is a deficient number, since it is larger than the sum of its proper divisors (11119347).

21002769 is a wasteful number, since it uses less digits than its factorization.

21002769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137296 (or 137293 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 21002769 is about 4582.8778076663. The cubic root of 21002769 is about 275.9045432338.

The spelling of 21002769 in words is "twenty-one million, two thousand, seven hundred sixty-nine".