991334400 has 312 divisors, whose sum is σ = 3753968064. Its totient is φ = 226099200.

The previous prime is 991334389. The next prime is 991334459. The reversal of 991334400 is 4433199.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2150170 + ... + 2150630.

Almost surely, 2^991334400 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 991334400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1876984032).

991334400 is an abundant number, since it is smaller than the sum of its proper divisors (2762633664).

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

991334400 is a wasteful number, since it uses less digits than its factorization.

991334400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 505 (or 478 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 33.

The square root of 991334400 is about 31485.4633124558. The cubic root of 991334400 is about 997.1030826402.

Adding to 991334400 its reverse (4433199), we get a palindrome (995767599).

The spelling of 991334400 in words is "nine hundred ninety-one million, three hundred thirty-four thousand, four hundred".