3121420021 has 4 divisors (see below), whose sum is σ = 3121799200. Its totient is φ = 3121040844.

The previous prime is 3121420019. The next prime is 3121420037. The reversal of 3121420021 is 1200241213.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 3121420021 - 2¹ = 3121420019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 3121419977 and 3121420004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3121420921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 176961 + ... + 193798.

It is an arithmetic number, because the mean of its divisors is an integer number (780449800).

Almost surely, 2^3121420021 is an apocalyptic number.

It is an amenable number.

3121420021 is a deficient number, since it is larger than the sum of its proper divisors (379179).

3121420021 is an equidigital number, since it uses as much as digits as its factorization.

3121420021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 379178.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 3121420021 is about 55869.6699560683. The cubic root of 3121420021 is about 1461.4503666013.

Adding to 3121420021 its reverse (1200241213), we get a palindrome (4321661234).

The spelling of 3121420021 in words is "three billion, one hundred twenty-one million, four hundred twenty thousand, twenty-one".