31213121011 has 4 divisors (see below), whose sum is σ = 31217493024. Its totient is φ = 31208749000.

The previous prime is 31213121003. The next prime is 31213121021. The reversal of 31213121011 is 11012131213.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 31213121011 - 2³ = 31213121003 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31213121021) 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, 2175280 + ... + 2189581.

It is an arithmetic number, because the mean of its divisors is an integer number (7804373256).

Almost surely, 2^31213121011 is an apocalyptic number.

31213121011 is a deficient number, since it is larger than the sum of its proper divisors (4372013).

31213121011 is an equidigital number, since it uses as much as digits as its factorization.

31213121011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4372012.

The product of its (nonzero) digits is 36, while the sum is 16.

Adding to 31213121011 its reverse (11012131213), we get a palindrome (42225252224).

The spelling of 31213121011 in words is "thirty-one billion, two hundred thirteen million, one hundred twenty-one thousand, eleven".