1321661577 has 4 divisors (see below), whose sum is σ = 1762215440. Its totient is φ = 881107716.

The previous prime is 1321661519. The next prime is 1321661587. The reversal of 1321661577 is 7751661231.

1321661577 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

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 not a de Polignac number, because 1321661577 - 2⁸ = 1321661321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1321661507) 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, 220276927 + ... + 220276932.

It is an arithmetic number, because the mean of its divisors is an integer number (440553860).

Almost surely, 2^1321661577 is an apocalyptic number.

It is an amenable number.

1321661577 is a deficient number, since it is larger than the sum of its proper divisors (440553863).

1321661577 is an equidigital number, since it uses as much as digits as its factorization.

1321661577 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440553862.

The product of its digits is 52920, while the sum is 39.

The square root of 1321661577 is about 36354.6637585881. The cubic root of 1321661577 is about 1097.4213916574.

The spelling of 1321661577 in words is "one billion, three hundred twenty-one million, six hundred sixty-one thousand, five hundred seventy-seven".