999667440 has 320 divisors, whose sum is σ = 3614054400. Its totient is φ = 253725696.

The previous prime is 999667421. The next prime is 999667441. The reversal of 999667440 is 44766999.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999667441) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4365246 + ... + 4365474.

It is an arithmetic number, because the mean of its divisors is an integer number (11293920).

Almost surely, 2^999667440 is an apocalyptic number.

999667440 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 999667440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1807027200).

999667440 is an abundant number, since it is smaller than the sum of its proper divisors (2614386960).

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

999667440 is a wasteful number, since it uses less digits than its factorization.

999667440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341 (or 329 counting only the distinct ones).

The product of its (nonzero) digits is 2939328, while the sum is 54.

The square root of 999667440 is about 31617.5179291481. The cubic root of 999667440 is about 999.8891343759.

The spelling of 999667440 in words is "nine hundred ninety-nine million, six hundred sixty-seven thousand, four hundred forty".