31123220101 has 4 divisors (see below), whose sum is σ = 32953997772. Its totient is φ = 29292442432.

The previous prime is 31123220077. The next prime is 31123220129. The reversal of 31123220101 is 10102232113.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 10102232113 = 19 ⋅531696427.

It can be written as a sum of positive squares in 2 ways, for example, as 8450389476 + 22672830625 = 91926^2 + 150575^2 .

It is a cyclic number.

It is not a de Polignac number, because 31123220101 - 2⁷ = 31123219973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31123280101) 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, 915388810 + ... + 915388843.

It is an arithmetic number, because the mean of its divisors is an integer number (8238499443).

Almost surely, 2^31123220101 is an apocalyptic number.

It is an amenable number.

31123220101 is a deficient number, since it is larger than the sum of its proper divisors (1830777671).

31123220101 is a wasteful number, since it uses less digits than its factorization.

31123220101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1830777670.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 31123220101 its reverse (10102232113), we get a palindrome (41225452214).

The spelling of 31123220101 in words is "thirty-one billion, one hundred twenty-three million, two hundred twenty thousand, one hundred one".