1397371561 has 2 divisors, whose sum is σ = 1397371562. Its totient is φ = 1397371560.

The previous prime is 1397371543. The next prime is 1397371567. The reversal of 1397371561 is 1651737931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1397339161 + 32400 = 37381^2 + 180^2 .

It is a cyclic number.

It is not a de Polignac number, because 1397371561 - 2²¹ = 1395274409 is a prime.

It is not a weakly prime, because it can be changed into another prime (1397371567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 698685780 + 698685781.

It is an arithmetic number, because the mean of its divisors is an integer number (698685781).

Almost surely, 2^1397371561 is an apocalyptic number.

It is an amenable number.

1397371561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1397371561 is an equidigital number, since it uses as much as digits as its factorization.

1397371561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 119070, while the sum is 43.

The square root of 1397371561 is about 37381.4333727320. The cubic root of 1397371561 is about 1117.9884069083.

The spelling of 1397371561 in words is "one billion, three hundred ninety-seven million, three hundred seventy-one thousand, five hundred sixty-one".