21252545 has 8 divisors (see below), whose sum is σ = 26845440. Its totient is φ = 16107120.

The previous prime is 21252509. The next prime is 21252547. The reversal of 21252545 is 54525212.

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

It is not a de Polignac number, because 21252545 - 2⁸ = 21252289 is a prime.

It is a super-3 number, since 3×21252545³ (a number of 23 digits) contains 333 as substring.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (21252547) 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, 111761 + ... + 111950.

It is an arithmetic number, because the mean of its divisors is an integer number (3355680).

Almost surely, 2^21252545 is an apocalyptic number.

It is an amenable number.

21252545 is a deficient number, since it is larger than the sum of its proper divisors (5592895).

21252545 is a wasteful number, since it uses less digits than its factorization.

21252545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223735.

The product of its digits is 4000, while the sum is 26.

The square root of 21252545 is about 4610.0482643894. The cubic root of 21252545 is about 276.9939699887.

Adding to 21252545 its reverse (54525212), we get a palindrome (75777757).

The spelling of 21252545 in words is "twenty-one million, two hundred fifty-two thousand, five hundred forty-five".