21857874 has 16 divisors (see below), whose sum is σ = 44051040. Its totient is φ = 7230080.

The previous prime is 21857873. The next prime is 21857887. The reversal of 21857874 is 47875812.

It is not an unprimeable number, because it can be changed into a prime (21857873) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 13119 + ... + 14690.

It is an arithmetic number, because the mean of its divisors is an integer number (2753190).

Almost surely, 2^21857874 is an apocalyptic number.

21857874 is an abundant number, since it is smaller than the sum of its proper divisors (22193166).

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

21857874 is a wasteful number, since it uses less digits than its factorization.

21857874 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27945.

The product of its digits is 125440, while the sum is 42.

The square root of 21857874 is about 4675.2405285718. The cubic root of 21857874 is about 279.5992310678.

The spelling of 21857874 in words is "twenty-one million, eight hundred fifty-seven thousand, eight hundred seventy-four".