20995997 has 8 divisors (see below), whose sum is σ = 23437920. Its totient is φ = 18642960.

The previous prime is 20995993. The next prime is 20996009. The reversal of 20995997 is 79959902.

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

It is a cyclic number.

It is not a de Polignac number, because 20995997 - 2² = 20995993 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20995993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21722 + ... + 22667.

It is an arithmetic number, because the mean of its divisors is an integer number (2929740).

Almost surely, 2^20995997 is an apocalyptic number.

It is an amenable number.

20995997 is a deficient number, since it is larger than the sum of its proper divisors (2441923).

20995997 is a wasteful number, since it uses less digits than its factorization.

20995997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44443.

The product of its (nonzero) digits is 459270, while the sum is 50.

The square root of 20995997 is about 4582.1389110327. The cubic root of 20995997 is about 275.8748864075.

The spelling of 20995997 in words is "twenty million, nine hundred ninety-five thousand, nine hundred ninety-seven".