1221010011 has 16 divisors (see below), whose sum is σ = 1948050720. Its totient is φ = 751390560.

The previous prime is 1221009973. The next prime is 1221010013. The reversal of 1221010011 is 1100101221.

It is a happy number.

It is not a de Polignac number, because 1221010011 - 2⁷ = 1221009883 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 1221009975 and 1221010002.

It is not an unprimeable number, because it can be changed into a prime (1221010013) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1738980 + ... + 1739681.

It is an arithmetic number, because the mean of its divisors is an integer number (121753170).

Almost surely, 2^1221010011 is an apocalyptic number.

1221010011 is a deficient number, since it is larger than the sum of its proper divisors (727040709).

1221010011 is a wasteful number, since it uses less digits than its factorization.

1221010011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3478683 (or 3478677 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

The square root of 1221010011 is about 34942.9536673705. The cubic root of 1221010011 is about 1068.8245195192.

Adding to 1221010011 its reverse (1100101221), we get a palindrome (2321111232).

The spelling of 1221010011 in words is "one billion, two hundred twenty-one million, ten thousand, eleven".