9945990 has 48 divisors (see below), whose sum is σ = 26823888. Its totient is φ = 2651616.

The previous prime is 9945983. The next prime is 9945997. The reversal of 9945990 is 995499.

It is a happy number.

9945990 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (9945983) and next prime (9945997).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9945997) 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, 384 + ... + 4476.

It is an arithmetic number, because the mean of its divisors is an integer number (558831).

Almost surely, 2^9945990 is an apocalyptic number.

9945990 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 9945990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13411944).

9945990 is an abundant number, since it is smaller than the sum of its proper divisors (16877898).

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

9945990 is a wasteful number, since it uses less digits than its factorization.

9945990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4115 (or 4103 counting only the distinct ones).

The product of its (nonzero) digits is 131220, while the sum is 45.

The square root of 9945990 is about 3153.7263673312. The cubic root of 9945990 is about 215.0548985462.

The spelling of 9945990 in words is "nine million, nine hundred forty-five thousand, nine hundred ninety".