1521391 has 2 divisors, whose sum is σ = 1521392. Its totient is φ = 1521390.

The previous prime is 1521371. The next prime is 1521397. The reversal of 1521391 is 1931251.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1521391 - 2⁹ = 1520879 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1521397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 760695 + 760696.

It is an arithmetic number, because the mean of its divisors is an integer number (760696).

2^1521391 is an apocalyptic number.

1521391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1521391 is an equidigital number, since it uses as much as digits as its factorization.

1521391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 270, while the sum is 22.

The square root of 1521391 is about 1233.4467965826. The cubic root of 1521391 is about 115.0130042005.

The spelling of 1521391 in words is "one million, five hundred twenty-one thousand, three hundred ninety-one".