1091991010 has 32 divisors (see below), whose sum is σ = 2237507712. Its totient is φ = 379822080.

The previous prime is 1091991001. The next prime is 1091991011. The reversal of 1091991010 is 101991901.

It is not an unprimeable number, because it can be changed into a prime (1091991011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 213279 + ... + 218338.

It is an arithmetic number, because the mean of its divisors is an integer number (69922116).

Almost surely, 2^1091991010 is an apocalyptic number.

1091991010 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1091991010 is an abundant number, since it is smaller than the sum of its proper divisors (1145516702).

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

1091991010 is a wasteful number, since it uses less digits than its factorization.

1091991010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431658.

The product of its (nonzero) digits is 729, while the sum is 31.

The square root of 1091991010 is about 33045.2872585487. The cubic root of 1091991010 is about 1029.7687010085.

The spelling of 1091991010 in words is "one billion, ninety-one million, nine hundred ninety-one thousand, ten".