5181624781 has 4 divisors (see below), whose sum is σ = 5321668732. Its totient is φ = 5041580832.

The previous prime is 5181624757. The next prime is 5181624841. The reversal of 5181624781 is 1874261815.

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

It can be written as a sum of positive squares in 2 ways, for example, as 3663275625 + 1518349156 = 60525^2 + 38966^2 .

It is a cyclic number.

It is not a de Polignac number, because 5181624781 - 2⁹ = 5181624269 is a prime.

It is a super-2 number, since 2×5181624781² = 53698470742146595922, which 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 (5181624751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70021920 + ... + 70021993.

It is an arithmetic number, because the mean of its divisors is an integer number (1330417183).

Almost surely, 2^5181624781 is an apocalyptic number.

It is an amenable number.

5181624781 is a deficient number, since it is larger than the sum of its proper divisors (140043951).

5181624781 is a wasteful number, since it uses less digits than its factorization.

5181624781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140043950.

The product of its digits is 107520, while the sum is 43.

The square root of 5181624781 is about 71983.5035337959. The cubic root of 5181624781 is about 1730.4351184809.

The spelling of 5181624781 in words is "five billion, one hundred eighty-one million, six hundred twenty-four thousand, seven hundred eighty-one".