397191961 has 4 divisors (see below), whose sum is σ = 420556212. Its totient is φ = 373827712.

The previous prime is 397191937. The next prime is 397191973. The reversal of 397191961 is 169191793.

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

It can be written as a sum of positive squares in 2 ways, for example, as 220700736 + 176491225 = 14856^2 + 13285^2 .

It is a cyclic number.

It is not a de Polignac number, because 397191961 - 2⁹ = 397191449 is a prime.

It is a super-2 number, since 2×397191961² = 315522907766051042, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (397191901) 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, 11682100 + ... + 11682133.

It is an arithmetic number, because the mean of its divisors is an integer number (105139053).

Almost surely, 2^397191961 is an apocalyptic number.

It is an amenable number.

397191961 is a deficient number, since it is larger than the sum of its proper divisors (23364251).

397191961 is a wasteful number, since it uses less digits than its factorization.

397191961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23364250.

The product of its digits is 91854, while the sum is 46.

The square root of 397191961 is about 19929.6753862174. The cubic root of 397191961 is about 735.0780986628.

The spelling of 397191961 in words is "three hundred ninety-seven million, one hundred ninety-one thousand, nine hundred sixty-one".