2509991 has 4 divisors (see below), whose sum is σ = 2738184. Its totient is φ = 2281800.

The previous prime is 2509981. The next prime is 2509993. The reversal of 2509991 is 1999052.

2509991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2509991 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 (2509993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 114080 + ... + 114101.

It is an arithmetic number, because the mean of its divisors is an integer number (684546).

2^2509991 is an apocalyptic number.

2509991 is a deficient number, since it is larger than the sum of its proper divisors (228193).

2509991 is a wasteful number, since it uses less digits than its factorization.

2509991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 228192.

The product of its (nonzero) digits is 7290, while the sum is 35.

The square root of 2509991 is about 1584.2951113981. The cubic root of 2509991 is about 135.9014388250.

The spelling of 2509991 in words is "two million, five hundred nine thousand, nine hundred ninety-one".