20397969409 has 4 divisors (see below), whose sum is σ = 20895480900. Its totient is φ = 19900457920.

The previous prime is 20397969373. The next prime is 20397969413. The reversal of 20397969409 is 90496979302.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7643655184 + 12754314225 = 87428^2 + 112935^2 .

It is a cyclic number.

It is not a de Polignac number, because 20397969409 - 2¹⁷ = 20397838337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20397969499) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 248755684 + ... + 248755765.

It is an arithmetic number, because the mean of its divisors is an integer number (5223870225).

Almost surely, 2^20397969409 is an apocalyptic number.

It is an amenable number.

20397969409 is a deficient number, since it is larger than the sum of its proper divisors (497511491).

20397969409 is an equidigital number, since it uses as much as digits as its factorization.

20397969409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 497511490.

The product of its (nonzero) digits is 6613488, while the sum is 58.

The spelling of 20397969409 in words is "twenty billion, three hundred ninety-seven million, nine hundred sixty-nine thousand, four hundred nine".