20898649 has 2 divisors, whose sum is σ = 20898650. Its totient is φ = 20898648.

The previous prime is 20898629. The next prime is 20898667. The reversal of 20898649 is 94689802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19758025 + 1140624 = 4445^2 + 1068^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20898649 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20898599 and 20898608.

It is not a weakly prime, because it can be changed into another prime (20898629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10449324 + 10449325.

It is an arithmetic number, because the mean of its divisors is an integer number (10449325).

Almost surely, 2^20898649 is an apocalyptic number.

It is an amenable number.

20898649 is a deficient number, since it is larger than the sum of its proper divisors (1).

20898649 is an equidigital number, since it uses as much as digits as its factorization.

20898649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 248832, while the sum is 46.

The square root of 20898649 is about 4571.5040194667. The cubic root of 20898649 is about 275.4478608582.

The spelling of 20898649 in words is "twenty million, eight hundred ninety-eight thousand, six hundred forty-nine".