21327657 has 8 divisors (see below), whose sum is σ = 30624384. Its totient is φ = 13124688.

The previous prime is 21327653. The next prime is 21327689. The reversal of 21327657 is 75672312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21327657 - 2² = 21327653 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21327653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 273393 + ... + 273470.

It is an arithmetic number, because the mean of its divisors is an integer number (3828048).

Almost surely, 2^21327657 is an apocalyptic number.

It is an amenable number.

21327657 is a deficient number, since it is larger than the sum of its proper divisors (9296727).

21327657 is a wasteful number, since it uses less digits than its factorization.

21327657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 546879.

The product of its digits is 17640, while the sum is 33.

The square root of 21327657 is about 4618.1876315282. The cubic root of 21327657 is about 277.3199091225.

Adding to 21327657 its reverse (75672312), we get a palindrome (96999969).

The spelling of 21327657 in words is "twenty-one million, three hundred twenty-seven thousand, six hundred fifty-seven".