21553127 has 4 divisors (see below), whose sum is σ = 22820976. Its totient is φ = 20285280.

The previous prime is 21553123. The next prime is 21553141. The reversal of 21553127 is 72135512.

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 21553127 - 2² = 21553123 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21553096 and 21553105.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21553123) 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, 633899 + ... + 633932.

It is an arithmetic number, because the mean of its divisors is an integer number (5705244).

Almost surely, 2^21553127 is an apocalyptic number.

21553127 is a deficient number, since it is larger than the sum of its proper divisors (1267849).

21553127 is a wasteful number, since it uses less digits than its factorization.

21553127 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1267848.

The product of its digits is 2100, while the sum is 26.

The square root of 21553127 is about 4642.5345448365. The cubic root of 21553127 is about 278.2937348696.

Adding to 21553127 its reverse (72135512), we get a palindrome (93688639).

The spelling of 21553127 in words is "twenty-one million, five hundred fifty-three thousand, one hundred twenty-seven".