991669800 has 192 divisors, whose sum is σ = 3390408000. Its totient is φ = 237772800.

The previous prime is 991669799. The next prime is 991669801. The reversal of 991669800 is 8966199.

It is an interprime number because it is at equal distance from previous prime (991669799) and next prime (991669801).

It is a self number, because there is not a number n which added to its sum of digits gives 991669800.

It is not an unprimeable number, because it can be changed into a prime (991669801) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 639426 + ... + 640974.

It is an arithmetic number, because the mean of its divisors is an integer number (17658375).

Almost surely, 2^991669800 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 991669800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1695204000).

991669800 is an abundant number, since it is smaller than the sum of its proper divisors (2398738200).

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

991669800 is a wasteful number, since it uses less digits than its factorization.

991669800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1676 (or 1667 counting only the distinct ones).

The product of its (nonzero) digits is 209952, while the sum is 48.

The square root of 991669800 is about 31490.7891295217. The cubic root of 991669800 is about 997.2155205371.

The spelling of 991669800 in words is "nine hundred ninety-one million, six hundred sixty-nine thousand, eight hundred".