39978121 has 2 divisors, whose sum is σ = 39978122. Its totient is φ = 39978120.

The previous prime is 39978097. The next prime is 39978131. The reversal of 39978121 is 12187993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 39942400 + 35721 = 6320^2 + 189^2 .

It is a cyclic number.

It is not a de Polignac number, because 39978121 - 2¹¹ = 39976073 is a prime.

It is not a weakly prime, because it can be changed into another prime (39978131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19989060 + 19989061.

It is an arithmetic number, because the mean of its divisors is an integer number (19989061).

Almost surely, 2^39978121 is an apocalyptic number.

It is an amenable number.

39978121 is a deficient number, since it is larger than the sum of its proper divisors (1).

39978121 is an equidigital number, since it uses as much as digits as its factorization.

39978121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27216, while the sum is 40.

The square root of 39978121 is about 6322.8253969250. The cubic root of 39978121 is about 341.9328236902.

The spelling of 39978121 in words is "thirty-nine million, nine hundred seventy-eight thousand, one hundred twenty-one".