19972009 has 8 divisors (see below), whose sum is σ = 20384000. Its totient is φ = 19564416.

The previous prime is 19972003. The next prime is 19972019. The reversal of 19972009 is 90027991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a 3-Lehmer number, since φ(19972009) divides (19972009-1)³.

It is a cyclic number.

It is not a de Polignac number, because 19972009 - 2¹³ = 19963817 is a prime.

It is a super-2 number, since 2×19972009² = 797762286992162, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19972003) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8992 + ... + 10990.

It is an arithmetic number, because the mean of its divisors is an integer number (2548000).

Almost surely, 2^19972009 is an apocalyptic number.

It is an amenable number.

19972009 is a deficient number, since it is larger than the sum of its proper divisors (411991).

19972009 is a wasteful number, since it uses less digits than its factorization.

19972009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2199.

The product of its (nonzero) digits is 10206, while the sum is 37.

The square root of 19972009 is about 4469.0053703257. The cubic root of 19972009 is about 271.3150704317.

The spelling of 19972009 in words is "nineteen million, nine hundred seventy-two thousand, nine".