20899471 has 2 divisors, whose sum is σ = 20899472. Its totient is φ = 20899470.

The previous prime is 20899469. The next prime is 20899481. The reversal of 20899471 is 17499802.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20899471 - 2¹ = 20899469 is a prime.

It is a super-3 number, since 3×20899471³ (a number of 23 digits) contains 333 as substring.

Together with 20899469, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20899441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10449735 + 10449736.

It is an arithmetic number, because the mean of its divisors is an integer number (10449736).

Almost surely, 2^20899471 is an apocalyptic number.

20899471 is a deficient number, since it is larger than the sum of its proper divisors (1).

20899471 is an equidigital number, since it uses as much as digits as its factorization.

20899471 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 20899471 is about 4571.5939233488. The cubic root of 20899471 is about 275.4514721789.

The spelling of 20899471 in words is "twenty million, eight hundred ninety-nine thousand, four hundred seventy-one".