1091791554 has 64 divisors (see below), whose sum is σ = 2629545984. Its totient is φ = 295454016.

The previous prime is 1091791549. The next prime is 1091791579. The reversal of 1091791554 is 4551971901.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 94012 + ... + 104984.

It is an arithmetic number, because the mean of its divisors is an integer number (41086656).

Almost surely, 2^1091791554 is an apocalyptic number.

1091791554 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1091791554, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1314772992).

1091791554 is an abundant number, since it is smaller than the sum of its proper divisors (1537754430).

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

1091791554 is a wasteful number, since it uses less digits than its factorization.

1091791554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11111.

The product of its (nonzero) digits is 56700, while the sum is 42.

The square root of 1091791554 is about 33042.2692017361. The cubic root of 1091791554 is about 1029.7060002321.

The spelling of 1091791554 in words is "one billion, ninety-one million, seven hundred ninety-one thousand, five hundred fifty-four".