2661391 has 2 divisors, whose sum is σ = 2661392. Its totient is φ = 2661390.

The previous prime is 2661371. The next prime is 2661397. The reversal of 2661391 is 1931662.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2661391 - 2¹¹ = 2659343 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2661397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1330695 + 1330696.

It is an arithmetic number, because the mean of its divisors is an integer number (1330696).

2^2661391 is an apocalyptic number.

2661391 is a deficient number, since it is larger than the sum of its proper divisors (1).

2661391 is an equidigital number, since it uses as much as digits as its factorization.

2661391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1944, while the sum is 28.

The square root of 2661391 is about 1631.3770257056. The cubic root of 2661391 is about 138.5807459232.

The spelling of 2661391 in words is "two million, six hundred sixty-one thousand, three hundred ninety-one".