1387921 has 2 divisors, whose sum is σ = 1387922. Its totient is φ = 1387920.

The previous prime is 1387913. The next prime is 1387927. The reversal of 1387921 is 1297831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1347921 + 40000 = 1161^2 + 200^2 .

It is a cyclic number.

It is not a de Polignac number, because 1387921 - 2³ = 1387913 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1387927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 693960 + 693961.

It is an arithmetic number, because the mean of its divisors is an integer number (693961).

2^1387921 is an apocalyptic number.

It is an amenable number.

1387921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1387921 is an equidigital number, since it uses as much as digits as its factorization.

1387921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 31.

The square root of 1387921 is about 1178.1005899328. The cubic root of 1387921 is about 111.5462348557.

The spelling of 1387921 in words is "one million, three hundred eighty-seven thousand, nine hundred twenty-one".