1288222991 has 32 divisors (see below), whose sum is σ = 1513131840. Its totient is φ = 1096627840.

The previous prime is 1288222987. The next prime is 1288223017. The reversal of 1288222991 is 1992228821.

It is not a de Polignac number, because 1288222991 - 2² = 1288222987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1288222961) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6539105 + ... + 6539301.

It is an arithmetic number, because the mean of its divisors is an integer number (47285370).

Almost surely, 2^1288222991 is an apocalyptic number.

1288222991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1288222991 is a deficient number, since it is larger than the sum of its proper divisors (224908849).

1288222991 is an frugal number, since it uses more digits than its factorization.

1288222991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 281 (or 225 counting only the distinct ones).

The product of its digits is 82944, while the sum is 44.

The square root of 1288222991 is about 35891.8234560464. The cubic root of 1288222991 is about 1088.0871512219.

The spelling of 1288222991 in words is "one billion, two hundred eighty-eight million, two hundred twenty-two thousand, nine hundred ninety-one".