21857341 has 4 divisors (see below), whose sum is σ = 23844384. Its totient is φ = 19870300.

The previous prime is 21857293. The next prime is 21857357. The reversal of 21857341 is 14375812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21857341 - 2¹¹ = 21855293 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21854341) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 993505 + ... + 993526.

It is an arithmetic number, because the mean of its divisors is an integer number (5961096).

Almost surely, 2^21857341 is an apocalyptic number.

It is an amenable number.

21857341 is a deficient number, since it is larger than the sum of its proper divisors (1987043).

21857341 is a wasteful number, since it uses less digits than its factorization.

21857341 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1987042.

The product of its digits is 6720, while the sum is 31.

The square root of 21857341 is about 4675.1835258094. The cubic root of 21857341 is about 279.5969583917.

The spelling of 21857341 in words is "twenty-one million, eight hundred fifty-seven thousand, three hundred forty-one".