213267721 has 2 divisors, whose sum is σ = 213267722. Its totient is φ = 213267720.

The previous prime is 213267697. The next prime is 213267727. The reversal of 213267721 is 127762312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 206324496 + 6943225 = 14364^2 + 2635^2 .

It is a cyclic number.

It is not a de Polignac number, because 213267721 - 2¹¹ = 213265673 is a prime.

It is not a weakly prime, because it can be changed into another prime (213267727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106633860 + 106633861.

It is an arithmetic number, because the mean of its divisors is an integer number (106633861).

Almost surely, 2^213267721 is an apocalyptic number.

It is an amenable number.

213267721 is a deficient number, since it is larger than the sum of its proper divisors (1).

213267721 is an equidigital number, since it uses as much as digits as its factorization.

213267721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7056, while the sum is 31.

The square root of 213267721 is about 14603.6886093891. The cubic root of 213267721 is about 597.4593692136.

The spelling of 213267721 in words is "two hundred thirteen million, two hundred sixty-seven thousand, seven hundred twenty-one".