31211021101 has 4 divisors (see below), whose sum is σ = 33611868892. Its totient is φ = 28810173312.

The previous prime is 31211021047. The next prime is 31211021119. The reversal of 31211021101 is 10112011213.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19292932201 + 11918088900 = 138899^2 + 109170^2 .

It is a cyclic number.

It is not a de Polignac number, because 31211021101 - 2¹³ = 31211012909 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 2400847777 = 31211021101 / (3 + 1 + 2 + 1 + 1 + 0 + 2 + 1 + 1 + 0 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31211021131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1200423876 + ... + 1200423901.

It is an arithmetic number, because the mean of its divisors is an integer number (8402967223).

Almost surely, 2^31211021101 is an apocalyptic number.

It is an amenable number.

31211021101 is a deficient number, since it is larger than the sum of its proper divisors (2400847791).

31211021101 is a wasteful number, since it uses less digits than its factorization.

31211021101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2400847790.

The product of its (nonzero) digits is 12, while the sum is 13.

Adding to 31211021101 its reverse (10112011213), we get a palindrome (41323032314).

The spelling of 31211021101 in words is "thirty-one billion, two hundred eleven million, twenty-one thousand, one hundred one".