20497947 has 4 divisors (see below), whose sum is σ = 27330600. Its totient is φ = 13665296.

The previous prime is 20497921. The next prime is 20497993. The reversal of 20497947 is 74979402.

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

It is a cyclic number.

It is not a de Polignac number, because 20497947 - 2⁸ = 20497691 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20497899 and 20497908.

It is not an unprimeable number, because it can be changed into a prime (20497247) 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, 3416322 + ... + 3416327.

It is an arithmetic number, because the mean of its divisors is an integer number (6832650).

Almost surely, 2^20497947 is an apocalyptic number.

20497947 is a deficient number, since it is larger than the sum of its proper divisors (6832653).

20497947 is an equidigital number, since it uses as much as digits as its factorization.

20497947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6832652.

The product of its (nonzero) digits is 127008, while the sum is 42.

The square root of 20497947 is about 4527.4658474692. The cubic root of 20497947 is about 273.6760472450.

The spelling of 20497947 in words is "twenty million, four hundred ninety-seven thousand, nine hundred forty-seven".