1388021 has 2 divisors, whose sum is σ = 1388022. Its totient is φ = 1388020.

The previous prime is 1388011. The next prime is 1388029. The reversal of 1388021 is 1208831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1380625 + 7396 = 1175^2 + 86^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1388021 is a prime.

It is a super-3 number, since 3×1388021³ = 8022493338324999783, which contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1388029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 694010 + 694011.

It is an arithmetic number, because the mean of its divisors is an integer number (694011).

2^1388021 is an apocalyptic number.

It is an amenable number.

1388021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1388021 is an equidigital number, since it uses as much as digits as its factorization.

1388021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 1388021 is about 1178.1430303660. The cubic root of 1388021 is about 111.5489137679.

The spelling of 1388021 in words is "one million, three hundred eighty-eight thousand, twenty-one".