212641981 has 2 divisors, whose sum is σ = 212641982. Its totient is φ = 212641980.

The previous prime is 212641943. The next prime is 212641993. The reversal of 212641981 is 189146212.

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., 132825625 + 79816356 = 11525^2 + 8934^2 .

It is a cyclic number.

It is not a de Polignac number, because 212641981 - 2²⁷ = 78424253 is a prime.

It is a super-2 number, since 2×212641981² = 90433224167208722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212641921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106320990 + 106320991.

It is an arithmetic number, because the mean of its divisors is an integer number (106320991).

Almost surely, 2^212641981 is an apocalyptic number.

It is an amenable number.

212641981 is a deficient number, since it is larger than the sum of its proper divisors (1).

212641981 is an equidigital number, since it uses as much as digits as its factorization.

212641981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 34.

The square root of 212641981 is about 14582.2488320560. The cubic root of 212641981 is about 596.8744698551.

The spelling of 212641981 in words is "two hundred twelve million, six hundred forty-one thousand, nine hundred eighty-one".