31205004540121 has 4 divisors (see below), whose sum is σ = 31205031016500. Its totient is φ = 31204978063744.

The previous prime is 31205004540107. The next prime is 31205004540139. The reversal of 31205004540121 is 12104540050213.

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 11540560179600 + 19664444360521 = 3397140^2 + 4434461^2 .

It is a cyclic number.

It is not a de Polignac number, because 31205004540121 - 2⁵ = 31205004540089 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31205004540121.

It is not an unprimeable number, because it can be changed into a prime (31205004540821) 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, 11383696 + ... + 13856353.

It is an arithmetic number, because the mean of its divisors is an integer number (7801257754125).

Almost surely, 2^{31205004540121} is an apocalyptic number.

It is an amenable number.

31205004540121 is a deficient number, since it is larger than the sum of its proper divisors (26476379).

31205004540121 is a wasteful number, since it uses less digits than its factorization.

31205004540121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26476378.

The product of its (nonzero) digits is 4800, while the sum is 28.

Adding to 31205004540121 its reverse (12104540050213), we get a palindrome (43309544590334).

The spelling of 31205004540121 in words is "thirty-one trillion, two hundred five billion, four million, five hundred forty thousand, one hundred twenty-one".