1221505011 has 6 divisors (see below), whose sum is σ = 1764396140. Its totient is φ = 814336668.

The previous prime is 1221504989. The next prime is 1221505037. The reversal of 1221505011 is 1105051221.

1221505011 is a `hidden beast` number, since 12 + 2 + 150 + 501 + 1 = 666.

It is not a de Polignac number, because 1221505011 - 2⁵ = 1221504979 is a prime.

It is a super-2 number, since 2×1221505011² = 2984148983796220242, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221505081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 67861381 + ... + 67861398.

Almost surely, 2^1221505011 is an apocalyptic number.

1221505011 is a deficient number, since it is larger than the sum of its proper divisors (542891129).

1221505011 is a wasteful number, since it uses less digits than its factorization.

1221505011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135722785 (or 135722782 counting only the distinct ones).

The product of its (nonzero) digits is 100, while the sum is 18.

The square root of 1221505011 is about 34950.0359227283. The cubic root of 1221505011 is about 1068.9689345673.

Adding to 1221505011 its reverse (1105051221), we get a palindrome (2326556232).

The spelling of 1221505011 in words is "one billion, two hundred twenty-one million, five hundred five thousand, eleven".