2421345721 has 2 divisors, whose sum is σ = 2421345722. Its totient is φ = 2421345720.

The previous prime is 2421345713. The next prime is 2421345727. The reversal of 2421345721 is 1275431242.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1986039225 + 435306496 = 44565^2 + 20864^2 .

It is a cyclic number.

It is not a de Polignac number, because 2421345721 - 2³ = 2421345713 is a prime.

It is not a weakly prime, because it can be changed into another prime (2421345727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1210672860 + 1210672861.

It is an arithmetic number, because the mean of its divisors is an integer number (1210672861).

Almost surely, 2^2421345721 is an apocalyptic number.

It is an amenable number.

2421345721 is a deficient number, since it is larger than the sum of its proper divisors (1).

2421345721 is an equidigital number, since it uses as much as digits as its factorization.

2421345721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13440, while the sum is 31.

The square root of 2421345721 is about 49207.1714387243. The cubic root of 2421345721 is about 1342.8235038152.

Adding to 2421345721 its reverse (1275431242), we get a palindrome (3696776963).

The spelling of 2421345721 in words is "two billion, four hundred twenty-one million, three hundred forty-five thousand, seven hundred twenty-one".