42312121021 has 4 divisors (see below), whose sum is σ = 42319433344. Its totient is φ = 42304808700.

The previous prime is 42312121013. The next prime is 42312121087. The reversal of 42312121021 is 12012121324.

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 42312121021 - 2³ = 42312121013 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 42312121021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42312121921) 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, 3647475 + ... + 3659056.

It is an arithmetic number, because the mean of its divisors is an integer number (10579858336).

Almost surely, 2^42312121021 is an apocalyptic number.

It is an amenable number.

42312121021 is a deficient number, since it is larger than the sum of its proper divisors (7312323).

42312121021 is an equidigital number, since it uses as much as digits as its factorization.

42312121021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7312322.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 42312121021 its reverse (12012121324), we get a palindrome (54324242345).

The spelling of 42312121021 in words is "forty-two billion, three hundred twelve million, one hundred twenty-one thousand, twenty-one".