2151391 has 4 divisors (see below), whose sum is σ = 2346984. Its totient is φ = 1955800.

The previous prime is 2151377. The next prime is 2151403. The reversal of 2151391 is 1931512.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 2151391 - 2⁷ = 2151263 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2151301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 97780 + ... + 97801.

It is an arithmetic number, because the mean of its divisors is an integer number (586746).

2^2151391 is an apocalyptic number.

2151391 is a deficient number, since it is larger than the sum of its proper divisors (195593).

2151391 is a wasteful number, since it uses less digits than its factorization.

2151391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195592.

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

The square root of 2151391 is about 1466.7620802298. The cubic root of 2151391 is about 129.0941163625.

The spelling of 2151391 in words is "two million, one hundred fifty-one thousand, three hundred ninety-one".