1387021 has 2 divisors, whose sum is σ = 1387022. Its totient is φ = 1387020.

The previous prime is 1387007. The next prime is 1387037. The reversal of 1387021 is 1207831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1010025 + 376996 = 1005^2 + 614^2 .

It is a cyclic number.

It is not a de Polignac number, because 1387021 - 2¹⁷ = 1255949 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1386983 and 1387001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1387121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 693510 + 693511.

It is an arithmetic number, because the mean of its divisors is an integer number (693511).

2^1387021 is an apocalyptic number.

It is an amenable number.

1387021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1387021 is an equidigital number, since it uses as much as digits as its factorization.

1387021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 1387021 is about 1177.7185572114. The cubic root of 1387021 is about 111.5221188532.

The spelling of 1387021 in words is "one million, three hundred eighty-seven thousand, twenty-one".