197212891 has 4 divisors (see below), whose sum is σ = 197249832. Its totient is φ = 197175952.

The previous prime is 197212871. The next prime is 197212901. The reversal of 197212891 is 198212791.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 197212891 - 2⁵ = 197212859 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (197212861) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8761 + ... + 21706.

It is an arithmetic number, because the mean of its divisors is an integer number (49312458).

Almost surely, 2^197212891 is an apocalyptic number.

197212891 is a deficient number, since it is larger than the sum of its proper divisors (36941).

197212891 is an equidigital number, since it uses as much as digits as its factorization.

197212891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36940.

The product of its digits is 18144, while the sum is 40.

The square root of 197212891 is about 14043.2507276627. The cubic root of 197212891 is about 582.0743115908.

The spelling of 197212891 in words is "one hundred ninety-seven million, two hundred twelve thousand, eight hundred ninety-one".