999999996978 has 48 divisors (see below), whose sum is σ = 2137290047424. Its totient is φ = 311846803200.

The previous prime is 999999996977. The next prime is 999999996979. The reversal of 999999996978 is 879699999999.

It is an interprime number because it is at equal distance from previous prime (999999996977) and next prime (999999996979).

It is a Harshad number since it is a multiple of its sum of digits (102).

It is not an unprimeable number, because it can be changed into a prime (999999996977) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1437073 + ... + 2016228.

It is an arithmetic number, because the mean of its divisors is an integer number (44526875988).

Almost surely, 2^999999996978 is an apocalyptic number.

999999996978 is an abundant number, since it is smaller than the sum of its proper divisors (1137290050446).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

999999996978 is a wasteful number, since it uses less digits than its factorization.

999999996978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3453507 (or 3453490 counting only the distinct ones).

The product of its digits is 130173284304, while the sum is 102.

The spelling of 999999996978 in words is "nine hundred ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-six thousand, nine hundred seventy-eight".