1321921377 has 40 divisors (see below), whose sum is σ = 2389597056. Its totient is φ = 710944128.

The previous prime is 1321921327. The next prime is 1321921387. The reversal of 1321921377 is 7731291231.

It is a happy number.

It is not a de Polignac number, because 1321921377 - 2¹⁹ = 1321397089 is a prime.

It is a super-2 number, since 2×1321921377² = 3494952253939152258, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1321921327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 58933 + ... + 78210.

Almost surely, 2^1321921377 is an apocalyptic number.

1321921377 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1321921377 is a deficient number, since it is larger than the sum of its proper divisors (1067675679).

1321921377 is a wasteful number, since it uses less digits than its factorization.

1321921377 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137179 (or 137170 counting only the distinct ones).

The product of its digits is 15876, while the sum is 36.

The square root of 1321921377 is about 36358.2367146703. The cubic root of 1321921377 is about 1097.4932939263.

It can be divided in two parts, 13219 and 21377, that added together give a square (34596 = 186²).

The spelling of 1321921377 in words is "one billion, three hundred twenty-one million, nine hundred twenty-one thousand, three hundred seventy-seven".