221570939 has 2 divisors, whose sum is σ = 221570940. Its totient is φ = 221570938.

The previous prime is 221570893. The next prime is 221570977. The reversal of 221570939 is 939075122.

It is an a-pointer prime, because the next prime (221570977) can be obtained adding 221570939 to its sum of digits (38).

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221570939 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (221570539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110785469 + 110785470.

It is an arithmetic number, because the mean of its divisors is an integer number (110785470).

Almost surely, 2^221570939 is an apocalyptic number.

221570939 is a deficient number, since it is larger than the sum of its proper divisors (1).

221570939 is an equidigital number, since it uses as much as digits as its factorization.

221570939 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34020, while the sum is 38.

The square root of 221570939 is about 14885.2591176640. The cubic root of 221570939 is about 605.1145551811.

The spelling of 221570939 in words is "two hundred twenty-one million, five hundred seventy thousand, nine hundred thirty-nine".