21257148 has 24 divisors (see below), whose sum is σ = 54109440. Its totient is φ = 6441520.

The previous prime is 21257141. The next prime is 21257177. The reversal of 21257148 is 84175212.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21257141) 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, 80388 + ... + 80651.

It is an arithmetic number, because the mean of its divisors is an integer number (2254560).

Almost surely, 2^21257148 is an apocalyptic number.

It is an amenable number.

21257148 is an abundant number, since it is smaller than the sum of its proper divisors (32852292).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21257148 is a wasteful number, since it uses less digits than its factorization.

21257148 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161057 (or 161055 counting only the distinct ones).

The product of its digits is 4480, while the sum is 30.

The square root of 21257148 is about 4610.5474729147. The cubic root of 21257148 is about 277.0139662010.

The spelling of 21257148 in words is "twenty-one million, two hundred fifty-seven thousand, one hundred forty-eight".