21503769 has 16 divisors (see below), whose sum is σ = 33466368. Its totient is φ = 12025872.

The previous prime is 21503737. The next prime is 21503773. The reversal of 21503769 is 96730512.

It is not a de Polignac number, because 21503769 - 2⁵ = 21503737 is a prime.

It is a super-2 number, since 2×21503769² = 924824162410722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21503719) 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 15 ways as a sum of consecutive naturals, for example, 9907 + ... + 11880.

It is an arithmetic number, because the mean of its divisors is an integer number (2091648).

Almost surely, 2^21503769 is an apocalyptic number.

It is an amenable number.

21503769 is a deficient number, since it is larger than the sum of its proper divisors (11962599).

21503769 is a wasteful number, since it uses less digits than its factorization.

21503769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21844.

The product of its (nonzero) digits is 11340, while the sum is 33.

The square root of 21503769 is about 4637.2156516599. The cubic root of 21503769 is about 278.0811358506.

The spelling of 21503769 in words is "twenty-one million, five hundred three thousand, seven hundred sixty-nine".