212661997 has 2 divisors, whose sum is σ = 212661998. Its totient is φ = 212661996.

The previous prime is 212661989. The next prime is 212662001. The reversal of 212661997 is 799166212.

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., 202606756 + 10055241 = 14234^2 + 3171^2 .

It is a cyclic number.

It is not a de Polignac number, because 212661997 - 2³ = 212661989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212662997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106330998 + 106330999.

It is an arithmetic number, because the mean of its divisors is an integer number (106330999).

Almost surely, 2^212661997 is an apocalyptic number.

It is an amenable number.

212661997 is a deficient number, since it is larger than the sum of its proper divisors (1).

212661997 is an equidigital number, since it uses as much as digits as its factorization.

212661997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 81648, while the sum is 43.

The square root of 212661997 is about 14582.9351298015. The cubic root of 212661997 is about 596.8931972084.

The spelling of 212661997 in words is "two hundred twelve million, six hundred sixty-one thousand, nine hundred ninety-seven".