31123211136 has 128 divisors (see below), whose sum is σ = 88449993600. Its totient is φ = 9667123200.

The previous prime is 31123211083. The next prime is 31123211149. The reversal of 31123211136 is 63111232113.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 410091 + ... + 480021.

It is an arithmetic number, because the mean of its divisors is an integer number (691015575).

Almost surely, 2^31123211136 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31123211136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44224996800).

31123211136 is an abundant number, since it is smaller than the sum of its proper divisors (57326782464).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31123211136 is a wasteful number, since it uses less digits than its factorization.

31123211136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70028 (or 70016 counting only the distinct ones).

The product of its digits is 648, while the sum is 24.

Adding to 31123211136 its reverse (63111232113), we get a palindrome (94234443249).

The spelling of 31123211136 in words is "thirty-one billion, one hundred twenty-three million, two hundred eleven thousand, one hundred thirty-six".