39899521 has 2 divisors, whose sum is σ = 39899522. Its totient is φ = 39899520.

The previous prime is 39899491. The next prime is 39899543. The reversal of 39899521 is 12599893.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23415921 + 16483600 = 4839^2 + 4060^2 .

It is a cyclic number.

It is not a de Polignac number, because 39899521 - 2⁹ = 39899009 is a prime.

It is a super-3 number, since 3×39899521³ (a number of 24 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (39899591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19949760 + 19949761.

It is an arithmetic number, because the mean of its divisors is an integer number (19949761).

Almost surely, 2^39899521 is an apocalyptic number.

It is an amenable number.

39899521 is a deficient number, since it is larger than the sum of its proper divisors (1).

39899521 is an equidigital number, since it uses as much as digits as its factorization.

39899521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 174960, while the sum is 46.

The square root of 39899521 is about 6316.6067631284. The cubic root of 39899521 is about 341.7085881009.

The spelling of 39899521 in words is "thirty-nine million, eight hundred ninety-nine thousand, five hundred twenty-one".