2157091 has 2 divisors, whose sum is σ = 2157092. Its totient is φ = 2157090.

The previous prime is 2157041. The next prime is 2157097. The reversal of 2157091 is 1907512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2157091 - 2¹³ = 2148899 is a prime.

It is not a weakly prime, because it can be changed into another prime (2157097) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1078545 + 1078546.

It is an arithmetic number, because the mean of its divisors is an integer number (1078546).

2^2157091 is an apocalyptic number.

2157091 is a deficient number, since it is larger than the sum of its proper divisors (1).

2157091 is an equidigital number, since it uses as much as digits as its factorization.

2157091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 630, while the sum is 25.

The square root of 2157091 is about 1468.7038503388. The cubic root of 2157091 is about 129.2080252342.

It can be divided in two parts, 21 and 57091, that multiplied together give a palindrome (1198911).

The spelling of 2157091 in words is "two million, one hundred fifty-seven thousand, ninety-one".