1891149408 has 72 divisors (see below), whose sum is σ = 5385580200. Its totient is φ = 629489664.

The previous prime is 1891149391. The next prime is 1891149409. The reversal of 1891149408 is 8049411981.

1891149408 is a `hidden beast` number, since 18 + 91 + 149 + 408 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1891149409) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 217203 + ... + 225741.

It is an arithmetic number, because the mean of its divisors is an integer number (74799725).

Almost surely, 2^1891149408 is an apocalyptic number.

1891149408 is a gapful number since it is divisible by the number (18) 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 1891149408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2692790100).

1891149408 is an abundant number, since it is smaller than the sum of its proper divisors (3494430792).

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

1891149408 is a wasteful number, since it uses less digits than its factorization.

1891149408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9324 (or 9313 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 45.

The square root of 1891149408 is about 43487.3476772268. The cubic root of 1891149408 is about 1236.6361760980.

The spelling of 1891149408 in words is "one billion, eight hundred ninety-one million, one hundred forty-nine thousand, four hundred eight".