20889749 has 2 divisors, whose sum is σ = 20889750. Its totient is φ = 20889748.

The previous prime is 20889709. The next prime is 20889751. The reversal of 20889749 is 94798802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18879025 + 2010724 = 4345^2 + 1418^2 .

It is a cyclic number.

It is not a de Polignac number, because 20889749 - 2¹⁶ = 20824213 is a prime.

It is a super-2 number, since 2×20889749² = 872763226566002, which contains 22 as substring.

Together with 20889751, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20889709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10444874 + 10444875.

It is an arithmetic number, because the mean of its divisors is an integer number (10444875).

Almost surely, 2^20889749 is an apocalyptic number.

It is an amenable number.

20889749 is a deficient number, since it is larger than the sum of its proper divisors (1).

20889749 is an equidigital number, since it uses as much as digits as its factorization.

20889749 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 290304, while the sum is 47.

The square root of 20889749 is about 4570.5304943737. The cubic root of 20889749 is about 275.4087541191.

The spelling of 20889749 in words is "twenty million, eight hundred eighty-nine thousand, seven hundred forty-nine".