31201000021 has 4 divisors (see below), whose sum is σ = 31201984044. Its totient is φ = 31200016000.

The previous prime is 31201000009. The next prime is 31201000057. The reversal of 31201000021 is 12000010213.

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 2906395921 + 28294604100 = 53911^2 + 168210^2 .

It is a cyclic number.

It is not a de Polignac number, because 31201000021 - 2²¹ = 31198902869 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31200999971 and 31201000007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31201000421) 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, 442810 + ... + 508411.

It is an arithmetic number, because the mean of its divisors is an integer number (7800496011).

Almost surely, 2^31201000021 is an apocalyptic number.

It is an amenable number.

31201000021 is a deficient number, since it is larger than the sum of its proper divisors (984023).

31201000021 is an equidigital number, since it uses as much as digits as its factorization.

31201000021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 984022.

The product of its (nonzero) digits is 12, while the sum is 10.

Adding to 31201000021 its reverse (12000010213), we get a palindrome (43201010234).

The spelling of 31201000021 in words is "thirty-one billion, two hundred one million, twenty-one", and thus it is an aban number.