1321784387 has 16 divisors (see below), whose sum is σ = 1648864512. Its totient is φ = 1029383520.

The previous prime is 1321784341. The next prime is 1321784423. The reversal of 1321784387 is 7834871231.

It is not a de Polignac number, because 1321784387 - 2⁸ = 1321784131 is a prime.

It is a super-2 number, since 2×1321784387² = 3494227931433931538, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1321784327) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 177848 + ... + 185130.

It is an arithmetic number, because the mean of its divisors is an integer number (103054032).

Almost surely, 2^1321784387 is an apocalyptic number.

1321784387 is a deficient number, since it is larger than the sum of its proper divisors (327080125).

1321784387 is a wasteful number, since it uses less digits than its factorization.

1321784387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9658.

The product of its digits is 225792, while the sum is 44.

The square root of 1321784387 is about 36356.3527736213. The cubic root of 1321784387 is about 1097.4553817371.

The spelling of 1321784387 in words is "one billion, three hundred twenty-one million, seven hundred eighty-four thousand, three hundred eighty-seven".