39720881 has 2 divisors, whose sum is σ = 39720882. Its totient is φ = 39720880.

The previous prime is 39720859. The next prime is 39720893. The reversal of 39720881 is 18802793.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 38328481 + 1392400 = 6191^2 + 1180^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-39720881 is a prime.

It is a super-2 number, since 2×39720881² = 3155496774832322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (39720851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19860440 + 19860441.

It is an arithmetic number, because the mean of its divisors is an integer number (19860441).

Almost surely, 2^39720881 is an apocalyptic number.

It is an amenable number.

39720881 is a deficient number, since it is larger than the sum of its proper divisors (1).

39720881 is an equidigital number, since it uses as much as digits as its factorization.

39720881 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 39720881 is about 6302.4503964728. The cubic root of 39720881 is about 341.1978538934.

The spelling of 39720881 in words is "thirty-nine million, seven hundred twenty thousand, eight hundred eighty-one".