39459581621 has 2 divisors, whose sum is σ = 39459581622. Its totient is φ = 39459581620.

The previous prime is 39459581611. The next prime is 39459581687. The reversal of 39459581621 is 12618595493.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 36200770225 + 3258811396 = 190265^2 + 57086^2 .

It is a cyclic number.

It is not a de Polignac number, because 39459581621 - 2¹⁸ = 39459319477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (39459581611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19729790810 + 19729790811.

It is an arithmetic number, because the mean of its divisors is an integer number (19729790811).

Almost surely, 2^39459581621 is an apocalyptic number.

It is an amenable number.

39459581621 is a deficient number, since it is larger than the sum of its proper divisors (1).

39459581621 is an equidigital number, since it uses as much as digits as its factorization.

39459581621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2332800, while the sum is 53.

The spelling of 39459581621 in words is "thirty-nine billion, four hundred fifty-nine million, five hundred eighty-one thousand, six hundred twenty-one".