1091100021 has 8 divisors (see below), whose sum is σ = 1587054624. Its totient is φ = 661272720.

The previous prime is 1091099987. The next prime is 1091100119. The reversal of 1091100021 is 1200011901.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1091100021 - 2¹³ = 1091091829 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1091108021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16531786 + ... + 16531851.

It is an arithmetic number, because the mean of its divisors is an integer number (198381828).

Almost surely, 2^1091100021 is an apocalyptic number.

1091100021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1091100021 is a deficient number, since it is larger than the sum of its proper divisors (495954603).

1091100021 is a wasteful number, since it uses less digits than its factorization.

1091100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33063651.

The product of its (nonzero) digits is 18, while the sum is 15.

The square root of 1091100021 is about 33031.8031751220. The cubic root of 1091100021 is about 1029.4885514981.

Adding to 1091100021 its reverse (1200011901), we get a palindrome (2291111922).

The spelling of 1091100021 in words is "one billion, ninety-one million, one hundred thousand, twenty-one".