2978309 has 4 divisors (see below), whose sum is σ = 3047616. Its totient is φ = 2909004.

The previous prime is 2978303. The next prime is 2978317. The reversal of 2978309 is 9038792.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2978309 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 (2978303) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34589 + ... + 34674.

It is an arithmetic number, because the mean of its divisors is an integer number (761904).

2^2978309 is an apocalyptic number.

It is an amenable number.

2978309 is a deficient number, since it is larger than the sum of its proper divisors (69307).

2978309 is an equidigital number, since it uses as much as digits as its factorization.

2978309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69306.

The product of its (nonzero) digits is 27216, while the sum is 38.

The square root of 2978309 is about 1725.7777956620. Note that the first 4 decimals coincide. The cubic root of 2978309 is about 143.8765177277.

The spelling of 2978309 in words is "two million, nine hundred seventy-eight thousand, three hundred nine".