20489881 has 2 divisors, whose sum is σ = 20489882. Its totient is φ = 20489880.

The previous prime is 20489869. The next prime is 20489891. The reversal of 20489881 is 18898402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13286025 + 7203856 = 3645^2 + 2684^2 .

It is a cyclic number.

It is not a de Polignac number, because 20489881 - 2⁷ = 20489753 is a prime.

It is a super-2 number, since 2×20489881² = 839670446788322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20489891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10244940 + 10244941.

It is an arithmetic number, because the mean of its divisors is an integer number (10244941).

Almost surely, 2^20489881 is an apocalyptic number.

It is an amenable number.

20489881 is a deficient number, since it is larger than the sum of its proper divisors (1).

20489881 is an equidigital number, since it uses as much as digits as its factorization.

20489881 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 20489881 is about 4526.5749745254. The cubic root of 20489881 is about 273.6401451030.

The spelling of 20489881 in words is "twenty million, four hundred eighty-nine thousand, eight hundred eighty-one".