1288261421 has 4 divisors (see below), whose sum is σ = 1288637532. Its totient is φ = 1287885312.

The previous prime is 1288261409. The next prime is 1288261423. The reversal of 1288261421 is 1241628821.

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 103938025 + 1184323396 = 10195^2 + 34414^2 .

It is a cyclic number.

It is not a de Polignac number, because 1288261421 - 2⁶ = 1288261357 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1288261423) 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, 182870 + ... + 189783.

It is an arithmetic number, because the mean of its divisors is an integer number (322159383).

Almost surely, 2^1288261421 is an apocalyptic number.

It is an amenable number.

1288261421 is a deficient number, since it is larger than the sum of its proper divisors (376111).

1288261421 is an equidigital number, since it uses as much as digits as its factorization.

1288261421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 376110.

The product of its digits is 12288, while the sum is 35.

The square root of 1288261421 is about 35892.3588107552. The cubic root of 1288261421 is about 1088.0979709774.

The spelling of 1288261421 in words is "one billion, two hundred eighty-eight million, two hundred sixty-one thousand, four hundred twenty-one".