3158961781 has 4 divisors (see below), whose sum is σ = 3159095500. Its totient is φ = 3158828064.

The previous prime is 3158961779. The next prime is 3158961803. The reversal of 3158961781 is 1871698513.

It is a happy number.

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 1186802500 + 1972159281 = 34450^2 + 44409^2 .

It is a cyclic number.

It is not a de Polignac number, because 3158961781 - 2¹ = 3158961779 is a prime.

It is a super-2 number, since 2×3158961781² = 19958079067637383922, 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 (3158961881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20886 + ... + 82183.

It is an arithmetic number, because the mean of its divisors is an integer number (789773875).

Almost surely, 2^3158961781 is an apocalyptic number.

It is an amenable number.

3158961781 is a deficient number, since it is larger than the sum of its proper divisors (133719).

3158961781 is a wasteful number, since it uses less digits than its factorization.

3158961781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133718.

The product of its digits is 362880, while the sum is 49.

The square root of 3158961781 is about 56204.6419880066. The cubic root of 3158961781 is about 1467.2860566098.

The spelling of 3158961781 in words is "three billion, one hundred fifty-eight million, nine hundred sixty-one thousand, seven hundred eighty-one".