21074109 has 16 divisors (see below), whose sum is σ = 32428032. Its totient is φ = 11924208.

The previous prime is 21074099. The next prime is 21074111. The reversal of 21074109 is 90147012.

It is not a de Polignac number, because 21074109 - 2⁴ = 21074093 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21074129) 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, 2709 + ... + 7034.

It is an arithmetic number, because the mean of its divisors is an integer number (2026752).

Almost surely, 2^21074109 is an apocalyptic number.

It is an amenable number.

21074109 is a deficient number, since it is larger than the sum of its proper divisors (11353923).

21074109 is a wasteful number, since it uses less digits than its factorization.

21074109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9856.

The product of its (nonzero) digits is 504, while the sum is 24.

The square root of 21074109 is about 4590.6545284959. The cubic root of 21074109 is about 276.2165780632.

It can be divided in two parts, 2107 and 4109, that added together give a triangular number (6216 = T₁₁₁).

The spelling of 21074109 in words is "twenty-one million, seventy-four thousand, one hundred nine".