215680639 has 2 divisors, whose sum is σ = 215680640. Its totient is φ = 215680638.

The previous prime is 215680583. The next prime is 215680643. The reversal of 215680639 is 936086512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 215680639 - 2¹³ = 215672447 is a prime.

It is equal to p_11897743 and since 215680639 and 11897743 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (215680739) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107840319 + 107840320.

It is an arithmetic number, because the mean of its divisors is an integer number (107840320).

Almost surely, 2^215680639 is an apocalyptic number.

215680639 is a deficient number, since it is larger than the sum of its proper divisors (1).

215680639 is an equidigital number, since it uses as much as digits as its factorization.

215680639 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 77760, while the sum is 40.

The square root of 215680639 is about 14686.0695558751. The cubic root of 215680639 is about 599.7041495152.

The spelling of 215680639 in words is "two hundred fifteen million, six hundred eighty thousand, six hundred thirty-nine".