1221136081 has 4 divisors (see below), whose sum is σ = 1332148464. Its totient is φ = 1110123700.

The previous prime is 1221136057. The next prime is 1221136121. The reversal of 1221136081 is 1806311221.

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 1221136081 - 2¹⁹ = 1220611793 is a prime.

It is a super-2 number, since 2×1221136081² = 2982346656640077122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221136001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55506175 + ... + 55506196.

It is an arithmetic number, because the mean of its divisors is an integer number (333037116).

Almost surely, 2^1221136081 is an apocalyptic number.

1221136081 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221136081 is a deficient number, since it is larger than the sum of its proper divisors (111012383).

1221136081 is a wasteful number, since it uses less digits than its factorization.

1221136081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111012382.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 1221136081 is about 34944.7575610420. The cubic root of 1221136081 is about 1068.8613038395.

The spelling of 1221136081 in words is "one billion, two hundred twenty-one million, one hundred thirty-six thousand, eighty-one".