397687729 has 8 divisors (see below), whose sum is σ = 410803560. Its totient is φ = 384696576.

The previous prime is 397687723. The next prime is 397687781. The reversal of 397687729 is 927786793.

It can be written as a sum of positive squares in 4 ways, for example, as 332077729 + 65610000 = 18223^2 + 8100^2 .

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 397687729 - 2¹¹ = 397685681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (397687723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24664 + ... + 37465.

It is an arithmetic number, because the mean of its divisors is an integer number (51350445).

Almost surely, 2^397687729 is an apocalyptic number.

It is an amenable number.

397687729 is a deficient number, since it is larger than the sum of its proper divisors (13115831).

397687729 is a wasteful number, since it uses less digits than its factorization.

397687729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62339.

The product of its digits is 8001504, while the sum is 58.

The square root of 397687729 is about 19942.1094420826. The cubic root of 397687729 is about 735.3838086766.

The spelling of 397687729 in words is "three hundred ninety-seven million, six hundred eighty-seven thousand, seven hundred twenty-nine".