1397948021 has 2 divisors, whose sum is σ = 1397948022. Its totient is φ = 1397948020.

The previous prime is 1397947979. The next prime is 1397948053. The reversal of 1397948021 is 1208497931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1360872100 + 37075921 = 36890^2 + 6089^2 .

It is an emirp because it is prime and its reverse (1208497931) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1397948021 - 2¹⁴ = 1397931637 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1397948081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 698974010 + 698974011.

It is an arithmetic number, because the mean of its divisors is an integer number (698974011).

Almost surely, 2^1397948021 is an apocalyptic number.

It is an amenable number.

1397948021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1397948021 is an equidigital number, since it uses as much as digits as its factorization.

1397948021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108864, while the sum is 44.

The square root of 1397948021 is about 37389.1430899399. The cubic root of 1397948021 is about 1118.1421209748.

The spelling of 1397948021 in words is "one billion, three hundred ninety-seven million, nine hundred forty-eight thousand, twenty-one".