20989497 has 4 divisors (see below), whose sum is σ = 27986000. Its totient is φ = 13992996.

The previous prime is 20989483. The next prime is 20989513. The reversal of 20989497 is 79498902.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20989497 - 2¹⁸ = 20727353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20989457) 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, 3498247 + ... + 3498252.

It is an arithmetic number, because the mean of its divisors is an integer number (6996500).

Almost surely, 2^20989497 is an apocalyptic number.

It is an amenable number.

20989497 is a deficient number, since it is larger than the sum of its proper divisors (6996503).

20989497 is an equidigital number, since it uses as much as digits as its factorization.

20989497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6996502.

The product of its (nonzero) digits is 326592, while the sum is 48.

The square root of 20989497 is about 4581.4295803821. The cubic root of 20989497 is about 275.8464147606.

The spelling of 20989497 in words is "twenty million, nine hundred eighty-nine thousand, four hundred ninety-seven".