1220661091 has 4 divisors (see below), whose sum is σ = 1314558112. Its totient is φ = 1126764072.

The previous prime is 1220661067. The next prime is 1220661103. The reversal of 1220661091 is 1901660221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1220661091 - 2⁵ = 1220661059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1220661031) 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, 46948491 + ... + 46948516.

It is an arithmetic number, because the mean of its divisors is an integer number (328639528).

Almost surely, 2^1220661091 is an apocalyptic number.

1220661091 is a deficient number, since it is larger than the sum of its proper divisors (93897021).

1220661091 is an equidigital number, since it uses as much as digits as its factorization.

1220661091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93897020.

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 1220661091 is about 34937.9606016150. The cubic root of 1220661091 is about 1068.7226995021.

The spelling of 1220661091 in words is "one billion, two hundred twenty million, six hundred sixty-one thousand, ninety-one".