21520127 has 4 divisors (see below), whose sum is σ = 21546096. Its totient is φ = 21494160.

The previous prime is 21520091. The next prime is 21520133. The reversal of 21520127 is 72102512.

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 21520127 - 2⁸ = 21519871 is a prime.

It is a super-2 number, since 2×21520127² = 926231732192258, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21520099 and 21520108.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21528127) 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, 11699 + ... + 13412.

It is an arithmetic number, because the mean of its divisors is an integer number (5386524).

Almost surely, 2^21520127 is an apocalyptic number.

21520127 is a deficient number, since it is larger than the sum of its proper divisors (25969).

21520127 is an equidigital number, since it uses as much as digits as its factorization.

21520127 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25968.

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 21520127 is about 4638.9790902741. The cubic root of 21520127 is about 278.1516304425.

Adding to 21520127 its reverse (72102512), we get a palindrome (93622639).

The spelling of 21520127 in words is "twenty-one million, five hundred twenty thousand, one hundred twenty-seven".