31561445243 has 4 divisors (see below), whose sum is σ = 33222573960. Its totient is φ = 29900316528.

The previous prime is 31561445239. The next prime is 31561445263. The reversal of 31561445243 is 34254416513.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34254416513 = 19 ⋅1802864027.

It is a cyclic number.

It is not a de Polignac number, because 31561445243 - 2² = 31561445239 is a prime.

It is a super-2 number, since 2×31561445243² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31561445197 and 31561445206.

It is not an unprimeable number, because it can be changed into a prime (31561445263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 830564330 + ... + 830564367.

It is an arithmetic number, because the mean of its divisors is an integer number (8305643490).

Almost surely, 2^31561445243 is an apocalyptic number.

31561445243 is a deficient number, since it is larger than the sum of its proper divisors (1661128717).

31561445243 is a wasteful number, since it uses less digits than its factorization.

31561445243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1661128716.

The product of its digits is 172800, while the sum is 38.

The spelling of 31561445243 in words is "thirty-one billion, five hundred sixty-one million, four hundred forty-five thousand, two hundred forty-three".