212153861 has 2 divisors, whose sum is σ = 212153862. Its totient is φ = 212153860.

The previous prime is 212153827. The next prime is 212153917. The reversal of 212153861 is 168351212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 179720836 + 32433025 = 13406^2 + 5695^2 .

It is a cyclic number.

It is not a de Polignac number, because 212153861 - 2¹⁸ = 211891717 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212143861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106076930 + 106076931.

It is an arithmetic number, because the mean of its divisors is an integer number (106076931).

Almost surely, 2^212153861 is an apocalyptic number.

It is an amenable number.

212153861 is a deficient number, since it is larger than the sum of its proper divisors (1).

212153861 is an equidigital number, since it uses as much as digits as its factorization.

212153861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2880, while the sum is 29.

The square root of 212153861 is about 14565.5024286840. The cubic root of 212153861 is about 596.4174111904.

The spelling of 212153861 in words is "two hundred twelve million, one hundred fifty-three thousand, eight hundred sixty-one".