240423215821 has 2 divisors, whose sum is σ = 240423215822. Its totient is φ = 240423215820.

The previous prime is 240423215801. The next prime is 240423215827. The reversal of 240423215821 is 128512324042.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 223681702500 + 16741513321 = 472950^2 + 129389^2 .

It is a cyclic number.

It is not a de Polignac number, because 240423215821 - 2⁵ = 240423215789 is a prime.

It is a super-2 number, since 2×240423215821² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (240423215827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 120211607910 + 120211607911.

It is an arithmetic number, because the mean of its divisors is an integer number (120211607911).

Almost surely, 2^240423215821 is an apocalyptic number.

It is an amenable number.

240423215821 is a deficient number, since it is larger than the sum of its proper divisors (1).

240423215821 is an equidigital number, since it uses as much as digits as its factorization.

240423215821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 30720, while the sum is 34.

Adding to 240423215821 its reverse (128512324042), we get a palindrome (368935539863).

The spelling of 240423215821 in words is "two hundred forty billion, four hundred twenty-three million, two hundred fifteen thousand, eight hundred twenty-one".