1291622521 has 4 divisors (see below), whose sum is σ = 1476140032. Its totient is φ = 1107105012.

The previous prime is 1291622491. The next prime is 1291622539. The reversal of 1291622521 is 1252261921.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1291622521 - 2⁷ = 1291622393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1291622551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 92258745 + ... + 92258758.

It is an arithmetic number, because the mean of its divisors is an integer number (369035008).

Almost surely, 2^1291622521 is an apocalyptic number.

It is an amenable number.

1291622521 is a deficient number, since it is larger than the sum of its proper divisors (184517511).

1291622521 is an equidigital number, since it uses as much as digits as its factorization.

1291622521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 184517510.

The product of its digits is 4320, while the sum is 31.

The square root of 1291622521 is about 35939.1502542840. The cubic root of 1291622521 is about 1089.0434390473.

The spelling of 1291622521 in words is "one billion, two hundred ninety-one million, six hundred twenty-two thousand, five hundred twenty-one".