7855138231 has 4 divisors (see below), whose sum is σ = 7870755312. Its totient is φ = 7839521152.

The previous prime is 7855138229. The next prime is 7855138237. The reversal of 7855138231 is 1328315587.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 7855138231 - 2¹ = 7855138229 is a prime.

It is a super-2 number, since 2×7855138231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7855138237) 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, 7807786 + ... + 7808791.

It is an arithmetic number, because the mean of its divisors is an integer number (1967688828).

Almost surely, 2^7855138231 is an apocalyptic number.

7855138231 is a deficient number, since it is larger than the sum of its proper divisors (15617081).

7855138231 is a wasteful number, since it uses less digits than its factorization.

7855138231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15617080.

The product of its digits is 201600, while the sum is 43.

The square root of 7855138231 is about 88629.2177049984. The cubic root of 7855138231 is about 1987.8545795971.

The spelling of 7855138231 in words is "seven billion, eight hundred fifty-five million, one hundred thirty-eight thousand, two hundred thirty-one".