1391561 has 2 divisors, whose sum is σ = 1391562. Its totient is φ = 1391560.

The previous prime is 1391557. The next prime is 1391563. The reversal of 1391561 is 1651931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1336336 + 55225 = 1156^2 + 235^2 .

It is a cyclic number.

It is not a de Polignac number, because 1391561 - 2² = 1391557 is a prime.

Together with 1391563, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1391561.

It is not a weakly prime, because it can be changed into another prime (1391563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 695780 + 695781.

It is an arithmetic number, because the mean of its divisors is an integer number (695781).

2^1391561 is an apocalyptic number.

It is an amenable number.

1391561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1391561 is an equidigital number, since it uses as much as digits as its factorization.

1391561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 810, while the sum is 26.

The square root of 1391561 is about 1179.6444379558. The cubic root of 1391561 is about 111.6436644782.

The spelling of 1391561 in words is "one million, three hundred ninety-one thousand, five hundred sixty-one".