1221111988 has 24 divisors (see below), whose sum is σ = 2258413920. Its totient is φ = 576108000.

The previous prime is 1221111977. The next prime is 1221112001. The reversal of 1221111988 is 8891111221.

It is a super-2 number, since 2×1221111988² = 2982228974474624288, which contains 22 as substring.

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12931 + ... + 51082.

It is an arithmetic number, because the mean of its divisors is an integer number (94100580).

Almost surely, 2^1221111988 is an apocalyptic number.

It is an amenable number.

1221111988 is a deficient number, since it is larger than the sum of its proper divisors (1037301932).

1221111988 is a wasteful number, since it uses less digits than its factorization.

1221111988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64287 (or 64285 counting only the distinct ones).

The product of its digits is 2304, while the sum is 34.

The square root of 1221111988 is about 34944.4128295211. The cubic root of 1221111988 is about 1068.8542742531.

The spelling of 1221111988 in words is "one billion, two hundred twenty-one million, one hundred eleven thousand, nine hundred eighty-eight".