999961978 has 8 divisors (see below), whose sum is σ = 1548328320. Its totient is φ = 483852540.

The previous prime is 999961943. The next prime is 999961979. The reversal of 999961978 is 879169999.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (999961979) 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, 8064148 + ... + 8064271.

It is an arithmetic number, because the mean of its divisors is an integer number (193541040).

Almost surely, 2^999961978 is an apocalyptic number.

999961978 is a deficient number, since it is larger than the sum of its proper divisors (548366342).

999961978 is a wasteful number, since it uses less digits than its factorization.

999961978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16128452.

The product of its digits is 19840464, while the sum is 67.

The square root of 999961978 is about 31622.1754153632. The cubic root of 999961978 is about 999.9873258394.

The spelling of 999961978 in words is "nine hundred ninety-nine million, nine hundred sixty-one thousand, nine hundred seventy-eight".