1291551 has 4 divisors (see below), whose sum is σ = 1722072. Its totient is φ = 861032.

The previous prime is 1291547. The next prime is 1291567. The reversal of 1291551 is 1551921.

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

It is a cyclic number.

It is not a de Polignac number, because 1291551 - 2² = 1291547 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1291501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 215256 + ... + 215261.

It is an arithmetic number, because the mean of its divisors is an integer number (430518).

2^1291551 is an apocalyptic number.

1291551 is a deficient number, since it is larger than the sum of its proper divisors (430521).

1291551 is an equidigital number, since it uses as much as digits as its factorization.

1291551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430520.

The product of its digits is 450, while the sum is 24.

The square root of 1291551 is about 1136.4642537273. The cubic root of 1291551 is about 108.9023337479.

The spelling of 1291551 in words is "one million, two hundred ninety-one thousand, five hundred fifty-one".