213221377 has 2 divisors, whose sum is σ = 213221378. Its totient is φ = 213221376.

The previous prime is 213221251. The next prime is 213221381. The reversal of 213221377 is 773122312.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 129754881 + 83466496 = 11391^2 + 9136^2 .

It is a cyclic number.

It is not a de Polignac number, because 213221377 - 2¹¹ = 213219329 is a prime.

It is a super-2 number, since 2×213221377² = 90926711219552258, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (213221387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106610688 + 106610689.

It is an arithmetic number, because the mean of its divisors is an integer number (106610689).

It is a Proth number, since it is equal to 6507 ⋅ 2¹⁵ + 1 and 6507 < 2¹⁵.

Almost surely, 2^213221377 is an apocalyptic number.

It is an amenable number.

213221377 is a deficient number, since it is larger than the sum of its proper divisors (1).

213221377 is an equidigital number, since it uses as much as digits as its factorization.

213221377 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3528, while the sum is 28.

The square root of 213221377 is about 14602.1018007683. The cubic root of 213221377 is about 597.4160892417.

Adding to 213221377 its reverse (773122312), we get a palindrome (986343689).

The spelling of 213221377 in words is "two hundred thirteen million, two hundred twenty-one thousand, three hundred seventy-seven".