13971949209 has 45 divisors (see below), whose sum is σ = 21375477695. Its totient is φ = 8794303200.

The previous prime is 13971949183. The next prime is 13971949253. The reversal of 13971949209 is 90294917931.

It is a happy number.

The square root of 13971949209 is 118203.

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

13971949209 is a `hidden beast` number, since 1 + 397 + 1 + 9 + 49 + 209 = 666.

It can be written as a sum of positive squares in only one way, i.e., 673246809 + 13298702400 = 25947^2 + 115320^2 .

It is not a de Polignac number, because 13971949209 - 2¹³ = 13971941017 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13971949009) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 340779229 + ... + 340779269.

Almost surely, 2^13971949209 is an apocalyptic number.

13971949209 is the 118203-rd square number.

13971949209 is the 59102-nd centered octagonal number.

It is an amenable number.

13971949209 is a deficient number, since it is larger than the sum of its proper divisors (7403528486).

13971949209 is an frugal number, since it uses more digits than its factorization.

13971949209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212 (or 75 counting only the distinct ones).

The product of its (nonzero) digits is 1102248, while the sum is 54.

The spelling of 13971949209 in words is "thirteen billion, nine hundred seventy-one million, nine hundred forty-nine thousand, two hundred nine".