1091221505501 has 4 divisors (see below), whose sum is σ = 1091245106592. Its totient is φ = 1091197904412.

The previous prime is 1091221505497. The next prime is 1091221505597. The reversal of 1091221505501 is 1055051221901.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1091221505501 - 2² = 1091221505497 is a prime.

It is a super-2 number, since 2×1091221505501² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1091221505401) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11731055 + ... + 11823708.

It is an arithmetic number, because the mean of its divisors is an integer number (272811276648).

Almost surely, 2^{1091221505501} is an apocalyptic number.

It is an amenable number.

1091221505501 is a deficient number, since it is larger than the sum of its proper divisors (23601091).

1091221505501 is an equidigital number, since it uses as much as digits as its factorization.

1091221505501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23601090.

The product of its (nonzero) digits is 4500, while the sum is 32.

The spelling of 1091221505501 in words is "one trillion, ninety-one billion, two hundred twenty-one million, five hundred five thousand, five hundred one".