1272529661 has 4 divisors (see below), whose sum is σ = 1370416572. Its totient is φ = 1174642752.

The previous prime is 1272529651. The next prime is 1272529667. The reversal of 1272529661 is 1669252721.

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 136165561 + 1136364100 = 11669^2 + 33710^2 .

It is a cyclic number.

It is not a de Polignac number, because 1272529661 - 2⁶ = 1272529597 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1272529667) 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, 48943436 + ... + 48943461.

It is an arithmetic number, because the mean of its divisors is an integer number (342604143).

Almost surely, 2^1272529661 is an apocalyptic number.

It is an amenable number.

1272529661 is a deficient number, since it is larger than the sum of its proper divisors (97886911).

1272529661 is an equidigital number, since it uses as much as digits as its factorization.

1272529661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97886910.

The product of its digits is 90720, while the sum is 41.

The square root of 1272529661 is about 35672.5337059200. The cubic root of 1272529661 is about 1083.6506720250.

The spelling of 1272529661 in words is "one billion, two hundred seventy-two million, five hundred twenty-nine thousand, six hundred sixty-one".