215720887457 has 2 divisors, whose sum is σ = 215720887458. Its totient is φ = 215720887456.

The previous prime is 215720887441. The next prime is 215720887469. The reversal of 215720887457 is 754788027512.

215720887457 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 211052035216 + 4668852241 = 459404^2 + 68329^2 .

It is a cyclic number.

It is not a de Polignac number, because 215720887457 - 2⁴ = 215720887441 is a prime.

It is not a weakly prime, because it can be changed into another prime (215720887477) 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, 107860443728 + 107860443729.

It is an arithmetic number, because the mean of its divisors is an integer number (107860443729).

Almost surely, 2^215720887457 is an apocalyptic number.

It is an amenable number.

215720887457 is a deficient number, since it is larger than the sum of its proper divisors (1).

215720887457 is an equidigital number, since it uses as much as digits as its factorization.

215720887457 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8780800, while the sum is 56.

The spelling of 215720887457 in words is "two hundred fifteen billion, seven hundred twenty million, eight hundred eighty-seven thousand, four hundred fifty-seven".