21004127 has 4 divisors (see below), whose sum is σ = 21025200. Its totient is φ = 20983056.

The previous prime is 21004117. The next prime is 21004153. The reversal of 21004127 is 72140012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21004127 - 2²² = 16809823 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21004117) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8963 + ... + 11060.

It is an arithmetic number, because the mean of its divisors is an integer number (5256300).

Almost surely, 2^21004127 is an apocalyptic number.

21004127 is a deficient number, since it is larger than the sum of its proper divisors (21073).

21004127 is a wasteful number, since it uses less digits than its factorization.

21004127 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21072.

The product of its (nonzero) digits is 112, while the sum is 17.

The square root of 21004127 is about 4583.0259654512. The cubic root of 21004127 is about 275.9104895973.

Adding to 21004127 its reverse (72140012), we get a palindrome (93144139).

The spelling of 21004127 in words is "twenty-one million, four thousand, one hundred twenty-seven".