31231121221031 has 8 divisors (see below), whose sum is σ = 33282378952704. Its totient is φ = 29237645397400.

The previous prime is 31231121220931. The next prime is 31231121221037. The reversal of 31231121221031 is 13012212113213.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 31231121221031 - 2¹⁸ = 31231120958887 is a prime.

It is a super-2 number, since 2×31231121221031² (a number of 28 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31231121220988 and 31231121221006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31231121221037) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14445475895 + ... + 14445478056.

It is an arithmetic number, because the mean of its divisors is an integer number (4160297369088).

Almost surely, 2^{31231121221031} is an apocalyptic number.

31231121221031 is a deficient number, since it is larger than the sum of its proper divisors (2051257731673).

31231121221031 is a wasteful number, since it uses less digits than its factorization.

31231121221031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28890954021.

The product of its (nonzero) digits is 432, while the sum is 23.

Adding to 31231121221031 its reverse (13012212113213), we get a palindrome (44243333334244).

The spelling of 31231121221031 in words is "thirty-one trillion, two hundred thirty-one billion, one hundred twenty-one million, two hundred twenty-one thousand, thirty-one".