21252657 has 8 divisors (see below), whose sum is σ = 28358176. Its totient is φ = 14157792.

The previous prime is 21252653. The next prime is 21252677. The reversal of 21252657 is 75625212.

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

It is not a de Polignac number, because 21252657 - 2² = 21252653 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21252653) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6498 + ... + 9204.

It is an arithmetic number, because the mean of its divisors is an integer number (3544772).

Almost surely, 2^21252657 is an apocalyptic number.

It is an amenable number.

21252657 is a deficient number, since it is larger than the sum of its proper divisors (7105519).

21252657 is a wasteful number, since it uses less digits than its factorization.

21252657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5327.

The product of its digits is 8400, while the sum is 30.

The square root of 21252657 is about 4610.0604117517. The cubic root of 21252657 is about 276.9944565699.

Adding to 21252657 its reverse (75625212), we get a palindrome (96877869).

The spelling of 21252657 in words is "twenty-one million, two hundred fifty-two thousand, six hundred fifty-seven".