1397744857 has 2 divisors, whose sum is σ = 1397744858. Its totient is φ = 1397744856.

The previous prime is 1397744851. The next prime is 1397744897. The reversal of 1397744857 is 7584477931.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 718829721 + 678915136 = 26811^2 + 26056^2 .

It is a cyclic number.

It is not a de Polignac number, because 1397744857 - 2³ = 1397744849 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1397744798 and 1397744807.

It is not a weakly prime, because it can be changed into another prime (1397744851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 698872428 + 698872429.

It is an arithmetic number, because the mean of its divisors is an integer number (698872429).

Almost surely, 2^1397744857 is an apocalyptic number.

It is an amenable number.

1397744857 is a deficient number, since it is larger than the sum of its proper divisors (1).

1397744857 is an equidigital number, since it uses as much as digits as its factorization.

1397744857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5927040, while the sum is 55.

The square root of 1397744857 is about 37386.4261062755. The cubic root of 1397744857 is about 1118.0879517620.

The spelling of 1397744857 in words is "one billion, three hundred ninety-seven million, seven hundred forty-four thousand, eight hundred fifty-seven".