1978617 has 4 divisors (see below), whose sum is σ = 2638160. Its totient is φ = 1319076.

The previous prime is 1978597. The next prime is 1978631. The reversal of 1978617 is 7168791.

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 not a de Polignac number, because 1978617 - 2¹⁶ = 1913081 is a prime.

It is a super-3 number, since 3×1978617³ = 23238412857382233339, which contains 333 as substring.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1978687) 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, 329767 + ... + 329772.

It is an arithmetic number, because the mean of its divisors is an integer number (659540).

2^1978617 is an apocalyptic number.

It is an amenable number.

1978617 is a deficient number, since it is larger than the sum of its proper divisors (659543).

1978617 is an equidigital number, since it uses as much as digits as its factorization.

1978617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 659542.

The product of its digits is 21168, while the sum is 39.

The square root of 1978617 is about 1406.6332144522. The cubic root of 1978617 is about 125.5414803387.

The spelling of 1978617 in words is "one million, nine hundred seventy-eight thousand, six hundred seventeen".