20988481 has 2 divisors, whose sum is σ = 20988482. Its totient is φ = 20988480.

The previous prime is 20988467. The next prime is 20988493. The reversal of 20988481 is 18488902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14440000 + 6548481 = 3800^2 + 2559^2 .

It is a cyclic number.

It is not a de Polignac number, because 20988481 - 2⁹ = 20987969 is a prime.

It is a super-2 number, since 2×20988481² = 881032669374722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20988881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10494240 + 10494241.

It is an arithmetic number, because the mean of its divisors is an integer number (10494241).

Almost surely, 2^20988481 is an apocalyptic number.

It is an amenable number.

20988481 is a deficient number, since it is larger than the sum of its proper divisors (1).

20988481 is an equidigital number, since it uses as much as digits as its factorization.

20988481 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36864, while the sum is 40.

The square root of 20988481 is about 4581.3186966200. The cubic root of 20988481 is about 275.8419638920.

The spelling of 20988481 in words is "twenty million, nine hundred eighty-eight thousand, four hundred eighty-one".