21119409 has 12 divisors (see below), whose sum is σ = 30712500. Its totient is φ = 13984224.

The previous prime is 21119381. The next prime is 21119419. The reversal of 21119409 is 90491112.

It can be written as a sum of positive squares in 2 ways, for example, as 1272384 + 19847025 = 1128^2 + 4455^2 .

It is not a de Polignac number, because 21119409 - 2⁵ = 21119377 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21119419) 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, 6534 + ... + 9215.

It is an arithmetic number, because the mean of its divisors is an integer number (2559375).

Almost surely, 2^21119409 is an apocalyptic number.

It is an amenable number.

21119409 is a deficient number, since it is larger than the sum of its proper divisors (9593091).

21119409 is a wasteful number, since it uses less digits than its factorization.

21119409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15904 (or 15901 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 27.

The square root of 21119409 is about 4595.5858168464. The cubic root of 21119409 is about 276.4143508556.

It can be divided in two parts, 21119 and 409, that added together give a triangular number (21528 = T₂₀₇).

The spelling of 21119409 in words is "twenty-one million, one hundred nineteen thousand, four hundred nine".