39981940121 has 2 divisors, whose sum is σ = 39981940122. Its totient is φ = 39981940120.

The previous prime is 39981940079. The next prime is 39981940133. The reversal of 39981940121 is 12104918993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 32401800025 + 7580140096 = 180005^2 + 87064^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-39981940121 is a prime.

It is not a weakly prime, because it can be changed into another prime (39981940151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19990970060 + 19990970061.

It is an arithmetic number, because the mean of its divisors is an integer number (19990970061).

Almost surely, 2^39981940121 is an apocalyptic number.

It is an amenable number.

39981940121 is a deficient number, since it is larger than the sum of its proper divisors (1).

39981940121 is an equidigital number, since it uses as much as digits as its factorization.

39981940121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 139968, while the sum is 47.

The spelling of 39981940121 in words is "thirty-nine billion, nine hundred eighty-one million, nine hundred forty thousand, one hundred twenty-one".