212990891 has 2 divisors, whose sum is σ = 212990892. Its totient is φ = 212990890.

The previous prime is 212990867. The next prime is 212990927. The reversal of 212990891 is 198099212.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-212990891 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (212990191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106495445 + 106495446.

It is an arithmetic number, because the mean of its divisors is an integer number (106495446).

Almost surely, 2^212990891 is an apocalyptic number.

212990891 is a deficient number, since it is larger than the sum of its proper divisors (1).

212990891 is an equidigital number, since it uses as much as digits as its factorization.

212990891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23328, while the sum is 41.

The square root of 212990891 is about 14594.2074467920. The cubic root of 212990891 is about 597.2007485918.

The spelling of 212990891 in words is "two hundred twelve million, nine hundred ninety thousand, eight hundred ninety-one".