49821 has 4 divisors (see below), whose sum is σ = 66432. Its totient is φ = 33212.

The previous prime is 49811. The next prime is 49823. The reversal of 49821 is 12894.

49821 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

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 49821 - 2⁵ = 49789 is a prime.

It is a D-number.

It is a Curzon number.

49821 is a lucky number.

It is a nialpdrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 49791 and 49800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (49823) 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, 8301 + ... + 8306.

It is an arithmetic number, because the mean of its divisors is an integer number (16608).

2⁴⁹⁸²¹ is an apocalyptic number.

It is an amenable number.

49821 is a deficient number, since it is larger than the sum of its proper divisors (16611).

49821 is a wasteful number, since it uses less digits than its factorization.

49821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16610.

The product of its digits is 576, while the sum is 24.

The square root of 49821 is about 223.2061827101. The cubic root of 49821 is about 36.7962996437.

The spelling of 49821 in words is "forty-nine thousand, eight hundred twenty-one".