1288526221 has 4 divisors (see below), whose sum is σ = 1323351292. Its totient is φ = 1253701152.

The previous prime is 1288526201. The next prime is 1288526233. The reversal of 1288526221 is 1226258821.

It is the 14655-th star number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 659770596 + 628755625 = 25686^2 + 25075^2 .

It is a cyclic number.

It is not a de Polignac number, because 1288526221 - 2²¹ = 1286429069 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37), and also a Moran number because the ratio is a prime number: 34825033 = 1288526221 / (1 + 2 + 8 + 8 + 5 + 2 + 6 + 2 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1288526201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17412480 + ... + 17412553.

It is an arithmetic number, because the mean of its divisors is an integer number (330837823).

Almost surely, 2^1288526221 is an apocalyptic number.

It is an amenable number.

1288526221 is a deficient number, since it is larger than the sum of its proper divisors (34825071).

1288526221 is an equidigital number, since it uses as much as digits as its factorization.

1288526221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34825070.

The product of its digits is 30720, while the sum is 37.

The square root of 1288526221 is about 35896.0474286515. The cubic root of 1288526221 is about 1088.1725181149.

The spelling of 1288526221 in words is "one billion, two hundred eighty-eight million, five hundred twenty-six thousand, two hundred twenty-one".