1111551221 has 24 divisors (see below), whose sum is σ = 1271484864. Its totient is φ = 963480000.

The previous prime is 1111551197. The next prime is 1111551223. The reversal of 1111551221 is 1221551111.

It is a de Polignac number, because none of the positive numbers 2^k-1111551221 is a prime.

It is a super-2 number, since 2×1111551221² = 2471092233813181682, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1111551193 and 1111551202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1111551223) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 749801 + ... + 751281.

It is an arithmetic number, because the mean of its divisors is an integer number (52978536).

Almost surely, 2^1111551221 is an apocalyptic number.

1111551221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1111551221 is a deficient number, since it is larger than the sum of its proper divisors (159933643).

1111551221 is a wasteful number, since it uses less digits than its factorization.

1111551221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1625 (or 1594 counting only the distinct ones).

The product of its digits is 100, while the sum is 20.

The square root of 1111551221 is about 33339.9343280697. The cubic root of 1111551221 is about 1035.8809029747.

The spelling of 1111551221 in words is "one billion, one hundred eleven million, five hundred fifty-one thousand, two hundred twenty-one".