1091721240 has 224 divisors, whose sum is σ = 3812821200. Its totient is φ = 280869120.

The previous prime is 1091721193. The next prime is 1091721313. The reversal of 1091721240 is 421271901.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 844995 + ... + 846285.

Almost surely, 2^1091721240 is an apocalyptic number.

1091721240 is a gapful number since it is divisible by the number (10) 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 1091721240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1906410600).

1091721240 is an abundant number, since it is smaller than the sum of its proper divisors (2721099960).

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

1091721240 is a wasteful number, since it uses less digits than its factorization.

1091721240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1349 (or 1330 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The square root of 1091721240 is about 33041.2051838307. The cubic root of 1091721240 is about 1029.6838945771.

The spelling of 1091721240 in words is "one billion, ninety-one million, seven hundred twenty-one thousand, two hundred forty".