39807961 has 2 divisors, whose sum is σ = 39807962. Its totient is φ = 39807960.

The previous prime is 39807913. The next prime is 39807973. The reversal of 39807961 is 16970893.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 37748736 + 2059225 = 6144^2 + 1435^2 .

It is an emirp because it is prime and its reverse (16970893) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 39807961 - 2¹³ = 39799769 is a prime.

It is not a weakly prime, because it can be changed into another prime (39807991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19903980 + 19903981.

It is an arithmetic number, because the mean of its divisors is an integer number (19903981).

Almost surely, 2^39807961 is an apocalyptic number.

It is an amenable number.

39807961 is a deficient number, since it is larger than the sum of its proper divisors (1).

39807961 is an equidigital number, since it uses as much as digits as its factorization.

39807961 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 81648, while the sum is 43.

The square root of 39807961 is about 6309.3550383538. The cubic root of 39807961 is about 341.4470076770.

It can be divided in two parts, 3980 and 7961, that multiplied together give a triangular number (31684780 = T₇₉₆₀).

The spelling of 39807961 in words is "thirty-nine million, eight hundred seven thousand, nine hundred sixty-one".