1397039681 has 4 divisors (see below), whose sum is σ = 1397385264. Its totient is φ = 1396694100.

The previous prime is 1397039663. The next prime is 1397039731. The reversal of 1397039681 is 1869307931.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1869307931 = 6803 ⋅274777.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1397039681 is a prime.

It is a super-4 number, since 4×1397039681⁴ (a number of 38 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1397039621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166655 + ... + 174836.

It is an arithmetic number, because the mean of its divisors is an integer number (349346316).

Almost surely, 2^1397039681 is an apocalyptic number.

It is an amenable number.

1397039681 is a deficient number, since it is larger than the sum of its proper divisors (345583).

1397039681 is an equidigital number, since it uses as much as digits as its factorization.

1397039681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 345582.

The product of its (nonzero) digits is 244944, while the sum is 47.

The square root of 1397039681 is about 37376.9940070092. The cubic root of 1397039681 is about 1117.8998913502.

The spelling of 1397039681 in words is "one billion, three hundred ninety-seven million, thirty-nine thousand, six hundred eighty-one".