2191749840 has 400 divisors, whose sum is σ = 8779140480. Its totient is φ = 496419840.

The previous prime is 2191749839. The next prime is 2191749869. The reversal of 2191749840 is 489471912.

It is a happy number.

It is a super-2 number, since 2×2191749840² = 9607534722280051200, which contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 9570846 + ... + 9571074.

Almost surely, 2^2191749840 is an apocalyptic number.

2191749840 is a gapful number since it is divisible by the number (20) 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 2191749840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4389570240).

2191749840 is an abundant number, since it is smaller than the sum of its proper divisors (6587390640).

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

2191749840 is a wasteful number, since it uses less digits than its factorization.

2191749840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 472 (or 457 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The square root of 2191749840 is about 46816.1279902557. The cubic root of 2191749840 is about 1298.9636395158.

The spelling of 2191749840 in words is "two billion, one hundred ninety-one million, seven hundred forty-nine thousand, eight hundred forty".