42040312021 has 2 divisors, whose sum is σ = 42040312022. Its totient is φ = 42040312020.

The previous prime is 42040312009. The next prime is 42040312031. The reversal of 42040312021 is 12021304024.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29053202500 + 12987109521 = 170450^2 + 113961^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42040312021 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 42040312021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42040312031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21020156010 + 21020156011.

It is an arithmetic number, because the mean of its divisors is an integer number (21020156011).

Almost surely, 2^42040312021 is an apocalyptic number.

It is an amenable number.

42040312021 is a deficient number, since it is larger than the sum of its proper divisors (1).

42040312021 is an equidigital number, since it uses as much as digits as its factorization.

42040312021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 19.

Adding to 42040312021 its reverse (12021304024), we get a palindrome (54061616045).

It can be divided in two parts, 42040 and 312021, that added together give a triangular number (354061 = T₈₄₁).

The spelling of 42040312021 in words is "forty-two billion, forty million, three hundred twelve thousand, twenty-one".