999997680 has 320 divisors, whose sum is σ = 3620339712. Its totient is φ = 225899520.

The previous prime is 999997679. The next prime is 999997697. The reversal of 999997680 is 86799999.

999997680 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (66).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2610769 + ... + 2611151.

Almost surely, 2^999997680 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 999997680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1810169856).

999997680 is an abundant number, since it is smaller than the sum of its proper divisors (2620342032).

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

999997680 is a wasteful number, since it uses less digits than its factorization.

999997680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 476 (or 470 counting only the distinct ones).

The product of its (nonzero) digits is 19840464, while the sum is 66.

The square root of 999997680 is about 31622.7399192417. The cubic root of 999997680 is about 999.9992266661. Note that the first 3 decimals are identical.

The spelling of 999997680 in words is "nine hundred ninety-nine million, nine hundred ninety-seven thousand, six hundred eighty".