221170987 has 2 divisors, whose sum is σ = 221170988. Its totient is φ = 221170986.

The previous prime is 221170979. The next prime is 221170991. The reversal of 221170987 is 789071122.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221170987 - 2³ = 221170979 is a prime.

It is not a weakly prime, because it can be changed into another prime (221470987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110585493 + 110585494.

It is an arithmetic number, because the mean of its divisors is an integer number (110585494).

Almost surely, 2^221170987 is an apocalyptic number.

221170987 is a deficient number, since it is larger than the sum of its proper divisors (1).

221170987 is an equidigital number, since it uses as much as digits as its factorization.

221170987 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14112, while the sum is 37.

The square root of 221170987 is about 14871.8185505338. The cubic root of 221170987 is about 604.7502436528.

The spelling of 221170987 in words is "two hundred twenty-one million, one hundred seventy thousand, nine hundred eighty-seven".