21004499 has 2 divisors, whose sum is σ = 21004500. Its totient is φ = 21004498.

The previous prime is 21004471. The next prime is 21004513. The reversal of 21004499 is 99440012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21004499 - 2²⁴ = 4227283 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21004099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10502249 + 10502250.

It is an arithmetic number, because the mean of its divisors is an integer number (10502250).

Almost surely, 2^21004499 is an apocalyptic number.

21004499 is a deficient number, since it is larger than the sum of its proper divisors (1).

21004499 is an equidigital number, since it uses as much as digits as its factorization.

21004499 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 21004499 is about 4583.0665498114. The cubic root of 21004499 is about 275.9121184533.

The spelling of 21004499 in words is "twenty-one million, four thousand, four hundred ninety-nine".