6539978 has 4 divisors (see below), whose sum is σ = 9809970. Its totient is φ = 3269988.

The previous prime is 6539963. The next prime is 6539983. The reversal of 6539978 is 8799356.

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

It can be written as a sum of positive squares in only one way, i.e., 5822569 + 717409 = 2413^2 + 847^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1634993 + ... + 1634996.

Almost surely, 2^6539978 is an apocalyptic number.

6539978 is a deficient number, since it is larger than the sum of its proper divisors (3269992).

6539978 is a wasteful number, since it uses less digits than its factorization.

6539978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3269991.

The product of its digits is 408240, while the sum is 47.

The square root of 6539978 is about 2557.3380691649. The cubic root of 6539978 is about 187.0073872038.

The spelling of 6539978 in words is "six million, five hundred thirty-nine thousand, nine hundred seventy-eight".