213109961 has 2 divisors, whose sum is σ = 213109962. Its totient is φ = 213109960.

The previous prime is 213109957. The next prime is 213109991. The reversal of 213109961 is 169901312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 211149961 + 1960000 = 14531^2 + 1400^2 .

It is a cyclic number.

It is not a de Polignac number, because 213109961 - 2² = 213109957 is a prime.

It is not a weakly prime, because it can be changed into another prime (213109901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106554980 + 106554981.

It is an arithmetic number, because the mean of its divisors is an integer number (106554981).

Almost surely, 2^213109961 is an apocalyptic number.

It is an amenable number.

213109961 is a deficient number, since it is larger than the sum of its proper divisors (1).

213109961 is an equidigital number, since it uses as much as digits as its factorization.

213109961 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 213109961 is about 14598.2862350346. The cubic root of 213109961 is about 597.3120138297.

The spelling of 213109961 in words is "two hundred thirteen million, one hundred nine thousand, nine hundred sixty-one".