2001997890 has 128 divisors (see below), whose sum is σ = 5813856000. Its totient is φ = 488291328.

The previous prime is 2001997889. The next prime is 2001997969. The reversal of 2001997890 is 987991002.

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

It is a Curzon 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, 142042 + ... + 155498.

It is an arithmetic number, because the mean of its divisors is an integer number (45420750).

Almost surely, 2^2001997890 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2001997890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2906928000).

2001997890 is an abundant number, since it is smaller than the sum of its proper divisors (3811858110).

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

2001997890 is a wasteful number, since it uses less digits than its factorization.

2001997890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13521 (or 13515 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 45.

The square root of 2001997890 is about 44743.6910636572. The cubic root of 2001997890 is about 1260.3404408874.

The spelling of 2001997890 in words is "two billion, one million, nine hundred ninety-seven thousand, eight hundred ninety".