213241781 has 2 divisors, whose sum is σ = 213241782. Its totient is φ = 213241780.

The previous prime is 213241741. The next prime is 213241783. The reversal of 213241781 is 187142312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 172396900 + 40844881 = 13130^2 + 6391^2 .

It is a cyclic number.

It is not a de Polignac number, because 213241781 - 2¹⁰ = 213240757 is a prime.

It is a super-2 number, since 2×213241781² = 90944114328103922, which contains 22 as substring.

Together with 213241783, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213241783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106620890 + 106620891.

It is an arithmetic number, because the mean of its divisors is an integer number (106620891).

Almost surely, 2^213241781 is an apocalyptic number.

It is an amenable number.

213241781 is a deficient number, since it is larger than the sum of its proper divisors (1).

213241781 is an equidigital number, since it uses as much as digits as its factorization.

213241781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2688, while the sum is 29.

The square root of 213241781 is about 14602.8004505985. The cubic root of 213241781 is about 597.4351450063.

The spelling of 213241781 in words is "two hundred thirteen million, two hundred forty-one thousand, seven hundred eighty-one".