61031541781 has 12 divisors (see below), whose sum is σ = 75172104108. Its totient is φ = 49235528832.

The previous prime is 61031541763. The next prime is 61031541797. The reversal of 61031541781 is 18714513016.

It is a happy number.

61031541781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 38106553681 + 22924988100 = 195209^2 + 151410^2 .

It is not a de Polignac number, because 61031541781 - 2⁷ = 61031541653 is a prime.

It is a super-2 number, since 2×61031541781² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 61031541781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61031541721) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 36632746 + ... + 36634411.

It is an arithmetic number, because the mean of its divisors is an integer number (6264342009).

Almost surely, 2^61031541781 is an apocalyptic number.

It is an amenable number.

61031541781 is a deficient number, since it is larger than the sum of its proper divisors (14140562327).

61031541781 is a wasteful number, since it uses less digits than its factorization.

61031541781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73267188 (or 73267181 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 37.

The spelling of 61031541781 in words is "sixty-one billion, thirty-one million, five hundred forty-one thousand, seven hundred eighty-one".