1891990044 has 288 divisors, whose sum is σ = 6087070080. Its totient is φ = 483065856.

The previous prime is 1891990031. The next prime is 1891990081. The reversal of 1891990044 is 4400991981.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 12050814 + ... + 12050970.

It is an arithmetic number, because the mean of its divisors is an integer number (21135660).

Almost surely, 2^1891990044 is an apocalyptic number.

1891990044 is a gapful number since it is divisible by the number (14) 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 1891990044, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3043535040).

1891990044 is an abundant number, since it is smaller than the sum of its proper divisors (4195080036).

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

1891990044 is a wasteful number, since it uses less digits than its factorization.

1891990044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 317 (or 312 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 45.

The square root of 1891990044 is about 43497.0118973706. The cubic root of 1891990044 is about 1236.8193815938.

The spelling of 1891990044 in words is "one billion, eight hundred ninety-one million, nine hundred ninety thousand, forty-four".