393256987 has 4 divisors (see below), whose sum is σ = 397075120. Its totient is φ = 389438856.

The previous prime is 393256957. The next prime is 393256991. The reversal of 393256987 is 789652393.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 789652393 = 12739 ⋅61987.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-393256987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (393256957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1908912 + ... + 1909117.

It is an arithmetic number, because the mean of its divisors is an integer number (99268780).

Almost surely, 2^393256987 is an apocalyptic number.

393256987 is a deficient number, since it is larger than the sum of its proper divisors (3818133).

393256987 is a wasteful number, since it uses less digits than its factorization.

393256987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3818132.

The product of its digits is 2449440, while the sum is 52.

The square root of 393256987 is about 19830.7081820090. The cubic root of 393256987 is about 732.6425692123.

The spelling of 393256987 in words is "three hundred ninety-three million, two hundred fifty-six thousand, nine hundred eighty-seven".