21257874 has 48 divisors (see below), whose sum is σ = 50791104. Its totient is φ = 6372000.

The previous prime is 21257857. The next prime is 21257881. The reversal of 21257874 is 47875212.

21257874 is a `hidden beast` number, since 2 + 12 + 578 + 74 = 666.

It is a zygodrome in base 3.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19467 + ... + 20529.

It is an arithmetic number, because the mean of its divisors is an integer number (1058148).

Almost surely, 2^21257874 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21257874, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25395552).

21257874 is an abundant number, since it is smaller than the sum of its proper divisors (29533230).

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

21257874 is a wasteful number, since it uses less digits than its factorization.

21257874 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1183 (or 1180 counting only the distinct ones).

The product of its digits is 31360, while the sum is 36.

The square root of 21257874 is about 4610.6262047579. The cubic root of 21257874 is about 277.0171198045.

It can be divided in two parts, 2125 and 7874, that added together give a palindrome (9999).

The spelling of 21257874 in words is "twenty-one million, two hundred fifty-seven thousand, eight hundred seventy-four".