1329987961 has 3 divisors (see below), whose sum is σ = 1330024431. Its totient is φ = 1329951492.

The previous prime is 1329987959. The next prime is 1329987983. The reversal of 1329987961 is 1697899231.

The square root of 1329987961 is 36469.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1697899231 = 7 ⋅242557033.

It can be written as a sum of positive squares in only one way, i.e., 455011561 + 874976400 = 21331^2 + 29580^2 .

It is not a de Polignac number, because 1329987961 - 2¹ = 1329987959 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1329987161) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 18235 + ... + 54703.

It is an arithmetic number, because the mean of its divisors is an integer number (443341477).

Almost surely, 2^1329987961 is an apocalyptic number.

1329987961 is the 36469-th square number.

1329987961 is the 18235-th centered octagonal number.

It is an amenable number.

1329987961 is a deficient number, since it is larger than the sum of its proper divisors (36470).

1329987961 is an frugal number, since it uses more digits than its factorization.

1329987961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72938 (or 36469 counting only the distinct ones).

The product of its digits is 1469664, while the sum is 55.

The cubic root of 1329987961 is about 1099.7211306851.

The spelling of 1329987961 in words is "one billion, three hundred twenty-nine million, nine hundred eighty-seven thousand, nine hundred sixty-one".