2157391 has 2 divisors, whose sum is σ = 2157392. Its totient is φ = 2157390.

The previous prime is 2157361. The next prime is 2157401. The reversal of 2157391 is 1937512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2157391 - 2⁹ = 2156879 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2157301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1078695 + 1078696.

It is an arithmetic number, because the mean of its divisors is an integer number (1078696).

2^2157391 is an apocalyptic number.

2157391 is a deficient number, since it is larger than the sum of its proper divisors (1).

2157391 is an equidigital number, since it uses as much as digits as its factorization.

2157391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1890, while the sum is 28.

The square root of 2157391 is about 1468.8059776567. The cubic root of 2157391 is about 129.2140148765.

The spelling of 2157391 in words is "two million, one hundred fifty-seven thousand, three hundred ninety-one".