1978971 has 4 divisors (see below), whose sum is σ = 2638632. Its totient is φ = 1319312.

The previous prime is 1978927. The next prime is 1978981. The reversal of 1978971 is 1798791.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1798791 = 3 ⋅599597.

It is a cyclic number.

It is not a de Polignac number, because 1978971 - 2¹⁹ = 1454683 is a prime.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (1978981) 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, 329826 + ... + 329831.

It is an arithmetic number, because the mean of its divisors is an integer number (659658).

2^1978971 is an apocalyptic number.

1978971 is a deficient number, since it is larger than the sum of its proper divisors (659661).

1978971 is an equidigital number, since it uses as much as digits as its factorization.

1978971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 659660.

The product of its digits is 31752, while the sum is 42.

The square root of 1978971 is about 1406.7590412007. The cubic root of 1978971 is about 125.5489668868.

The spelling of 1978971 in words is "one million, nine hundred seventy-eight thousand, nine hundred seventy-one".