240421821 has 4 divisors (see below), whose sum is σ = 320562432. Its totient is φ = 160281212.

The previous prime is 240421817. The next prime is 240421849. The reversal of 240421821 is 128124042.

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 240421821 - 2² = 240421817 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 240421791 and 240421800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (240421891) 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, 40070301 + ... + 40070306.

It is an arithmetic number, because the mean of its divisors is an integer number (80140608).

Almost surely, 2^240421821 is an apocalyptic number.

It is an amenable number.

240421821 is a deficient number, since it is larger than the sum of its proper divisors (80140611).

240421821 is an equidigital number, since it uses as much as digits as its factorization.

240421821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80140610.

The product of its (nonzero) digits is 1024, while the sum is 24.

The square root of 240421821 is about 15505.5416222717. The cubic root of 240421821 is about 621.8103702975.

Adding to 240421821 its reverse (128124042), we get a palindrome (368545863).

The spelling of 240421821 in words is "two hundred forty million, four hundred twenty-one thousand, eight hundred twenty-one".