221538377 has 2 divisors, whose sum is σ = 221538378. Its totient is φ = 221538376.

The previous prime is 221538341. The next prime is 221538391. The reversal of 221538377 is 773835122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 177129481 + 44408896 = 13309^2 + 6664^2 .

It is a cyclic number.

It is not a de Polignac number, because 221538377 - 2²² = 217344073 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 221538377.

It is not a weakly prime, because it can be changed into another prime (221534377) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110769188 + 110769189.

It is an arithmetic number, because the mean of its divisors is an integer number (110769189).

Almost surely, 2^221538377 is an apocalyptic number.

It is an amenable number.

221538377 is a deficient number, since it is larger than the sum of its proper divisors (1).

221538377 is an equidigital number, since it uses as much as digits as its factorization.

221538377 is an evil number, because the sum of its binary digits is even.

The product of its digits is 70560, while the sum is 38.

The square root of 221538377 is about 14884.1653108261. The cubic root of 221538377 is about 605.0849112432.

The spelling of 221538377 in words is "two hundred twenty-one million, five hundred thirty-eight thousand, three hundred seventy-seven".