42821572721 has 2 divisors, whose sum is σ = 42821572722. Its totient is φ = 42821572720.

The previous prime is 42821572691. The next prime is 42821572727. The reversal of 42821572721 is 12727512824.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25643538496 + 17178034225 = 160136^2 + 131065^2 .

It is a cyclic number.

It is not a de Polignac number, because 42821572721 - 2⁶ = 42821572657 is a prime.

It is not a weakly prime, because it can be changed into another prime (42821572727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21410786360 + 21410786361.

It is an arithmetic number, because the mean of its divisors is an integer number (21410786361).

Almost surely, 2^42821572721 is an apocalyptic number.

It is an amenable number.

42821572721 is a deficient number, since it is larger than the sum of its proper divisors (1).

42821572721 is an equidigital number, since it uses as much as digits as its factorization.

42821572721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 125440, while the sum is 41.

The spelling of 42821572721 in words is "forty-two billion, eight hundred twenty-one million, five hundred seventy-two thousand, seven hundred twenty-one".