7864139 has 4 divisors (see below), whose sum is σ = 7885056. Its totient is φ = 7843224.

The previous prime is 7864127. The next prime is 7864147. The reversal of 7864139 is 9314687.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9314687 = 307 ⋅30341.

It is a cyclic number.

It is not a de Polignac number, because 7864139 - 2⁴ = 7864123 is a prime.

It is a super-2 number, since 2×7864139² = 123689364422642, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7864159) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9884 + ... + 10649.

It is an arithmetic number, because the mean of its divisors is an integer number (1971264).

Almost surely, 2^7864139 is an apocalyptic number.

7864139 is a deficient number, since it is larger than the sum of its proper divisors (20917).

7864139 is a wasteful number, since it uses less digits than its factorization.

7864139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20916.

The product of its digits is 36288, while the sum is 38.

The square root of 7864139 is about 2804.3072228271. The cubic root of 7864139 is about 198.8613547371.

The spelling of 7864139 in words is "seven million, eight hundred sixty-four thousand, one hundred thirty-nine".