7561518381 has 6 divisors (see below), whose sum is σ = 10922193230. Its totient is φ = 5041012248.

The previous prime is 7561518379. The next prime is 7561518397. The reversal of 7561518381 is 1838151657.

7561518381 is a `hidden beast` number, since 7 + 56 + 1 + 518 + 3 + 81 = 666.

It can be written as a sum of positive squares in only one way, i.e., 7511688900 + 49829481 = 86670^2 + 7059^2 .

It is not a de Polignac number, because 7561518381 - 2¹ = 7561518379 is a prime.

It is a super-3 number, since 3×7561518381³ (a number of 31 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7561511381) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 420084346 + ... + 420084363.

Almost surely, 2^7561518381 is an apocalyptic number.

It is an amenable number.

7561518381 is a deficient number, since it is larger than the sum of its proper divisors (3360674849).

7561518381 is a wasteful number, since it uses less digits than its factorization.

7561518381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 840168715 (or 840168712 counting only the distinct ones).

The product of its digits is 201600, while the sum is 45.

The square root of 7561518381 is about 86956.9915590460. The cubic root of 7561518381 is about 1962.7711721571.

The spelling of 7561518381 in words is "seven billion, five hundred sixty-one million, five hundred eighteen thousand, three hundred eighty-one".