39440768409 has 63 divisors (see below), whose sum is σ = 66811080063. Its totient is φ = 22420806912.

The previous prime is 39440768387. The next prime is 39440768429. The reversal of 39440768409 is 90486704493.

It is a happy number.

The square root of 39440768409 is 198597.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 9556040025 + 29884728384 = 97755^2 + 172872^2 .

It is a tau number, because it is divible by the number of its divisors (63).

It is not a de Polignac number, because 39440768409 - 2¹¹ = 39440766361 is a prime.

It is not an unprimeable number, because it can be changed into a prime (39440768429) by changing a digit.

It is a polite number, since it can be written in 62 ways as a sum of consecutive naturals, for example, 204356217 + ... + 204356409.

Almost surely, 2^39440768409 is an apocalyptic number.

39440768409 is the 198597-th square number.

39440768409 is the 99299-th centered octagonal number.

It is an amenable number.

39440768409 is a deficient number, since it is larger than the sum of its proper divisors (27370311654).

39440768409 is an frugal number, since it uses more digits than its factorization.

39440768409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 434 (or 203 counting only the distinct ones).

The product of its (nonzero) digits is 5225472, while the sum is 54.

The spelling of 39440768409 in words is "thirty-nine billion, four hundred forty million, seven hundred sixty-eight thousand, four hundred nine".