397729891 has 8 divisors (see below), whose sum is σ = 428515920. Its totient is φ = 366971232.

The previous prime is 397729877. The next prime is 397729939. The reversal of 397729891 is 198927793.

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

It is a cyclic number.

It is not a de Polignac number, because 397729891 - 2¹⁷ = 397598819 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (397729691) 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, 31221 + ... + 42073.

It is an arithmetic number, because the mean of its divisors is an integer number (53564490).

Almost surely, 2^397729891 is an apocalyptic number.

397729891 is a deficient number, since it is larger than the sum of its proper divisors (30786029).

397729891 is a wasteful number, since it uses less digits than its factorization.

397729891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13685.

The product of its digits is 1714608, while the sum is 55.

The square root of 397729891 is about 19943.1665238999. The cubic root of 397729891 is about 735.4097956962.

The spelling of 397729891 in words is "three hundred ninety-seven million, seven hundred twenty-nine thousand, eight hundred ninety-one".