1321072749 has 6 divisors (see below), whose sum is σ = 1908216206. Its totient is φ = 880715160.

The previous prime is 1321072721. The next prime is 1321072763. The reversal of 1321072749 is 9472701231.

It can be written as a sum of positive squares in only one way, i.e., 972317124 + 348755625 = 31182^2 + 18675^2 .

It is not a de Polignac number, because 1321072749 - 2⁹ = 1321072237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321072799) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 73392922 + ... + 73392939.

Almost surely, 2^1321072749 is an apocalyptic number.

It is an amenable number.

1321072749 is a deficient number, since it is larger than the sum of its proper divisors (587143457).

1321072749 is a wasteful number, since it uses less digits than its factorization.

1321072749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146785867 (or 146785864 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 36.

The square root of 1321072749 is about 36346.5644731383. The cubic root of 1321072749 is about 1097.2583926865.

The spelling of 1321072749 in words is "one billion, three hundred twenty-one million, seventy-two thousand, seven hundred forty-nine".