397611991 has 8 divisors (see below), whose sum is σ = 455106464. Its totient is φ = 340290720.

The previous prime is 397611941. The next prime is 397612001. The reversal of 397611991 is 199116793.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 397611991 - 2¹⁹ = 397087703 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (397611941) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38340 + ... + 47593.

It is an arithmetic number, because the mean of its divisors is an integer number (56888308).

Almost surely, 2^397611991 is an apocalyptic number.

397611991 is a deficient number, since it is larger than the sum of its proper divisors (57494473).

397611991 is an equidigital number, since it uses as much as digits as its factorization.

397611991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86601.

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

The square root of 397611991 is about 19940.2104051086. The cubic root of 397611991 is about 735.3371221007.

The spelling of 397611991 in words is "three hundred ninety-seven million, six hundred eleven thousand, nine hundred ninety-one".