40042542121 has 2 divisors, whose sum is σ = 40042542122. Its totient is φ = 40042542120.

The previous prime is 40042542109. The next prime is 40042542143. The reversal of 40042542121 is 12124524004.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 37631732121 + 2410810000 = 193989^2 + 49100^2 .

It is a cyclic number.

It is not a de Polignac number, because 40042542121 - 2¹¹ = 40042540073 is a prime.

It is not a weakly prime, because it can be changed into another prime (40042542181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20021271060 + 20021271061.

It is an arithmetic number, because the mean of its divisors is an integer number (20021271061).

Almost surely, 2^40042542121 is an apocalyptic number.

It is an amenable number.

40042542121 is a deficient number, since it is larger than the sum of its proper divisors (1).

40042542121 is an equidigital number, since it uses as much as digits as its factorization.

40042542121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2560, while the sum is 25.

The spelling of 40042542121 in words is "forty billion, forty-two million, five hundred forty-two thousand, one hundred twenty-one".