1272320521 has 4 divisors (see below), whose sum is σ = 1273307344. Its totient is φ = 1271333700.

The previous prime is 1272320513. The next prime is 1272320537. The reversal of 1272320521 is 1250232721.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1250232721 = 41 ⋅30493481.

It is a cyclic number.

It is not a de Polignac number, because 1272320521 - 2³ = 1272320513 is a prime.

It is a super-2 number, since 2×1272320521² = 3237599016315422882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1272420521) 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, 491475 + ... + 494056.

It is an arithmetic number, because the mean of its divisors is an integer number (318326836).

Almost surely, 2^1272320521 is an apocalyptic number.

It is an amenable number.

1272320521 is a deficient number, since it is larger than the sum of its proper divisors (986823).

1272320521 is an equidigital number, since it uses as much as digits as its factorization.

1272320521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 986822.

The product of its (nonzero) digits is 1680, while the sum is 25.

The square root of 1272320521 is about 35669.6021985107. The cubic root of 1272320521 is about 1083.5913028473.

The spelling of 1272320521 in words is "one billion, two hundred seventy-two million, three hundred twenty thousand, five hundred twenty-one".