20933989 has 2 divisors, whose sum is σ = 20933990. Its totient is φ = 20933988.

The previous prime is 20933981. The next prime is 20933999. The reversal of 20933989 is 98933902.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20930625 + 3364 = 4575^2 + 58^2 .

It is a cyclic number.

It is not a de Polignac number, because 20933989 - 2³ = 20933981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20933981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10466994 + 10466995.

It is an arithmetic number, because the mean of its divisors is an integer number (10466995).

Almost surely, 2^20933989 is an apocalyptic number.

It is an amenable number.

20933989 is a deficient number, since it is larger than the sum of its proper divisors (1).

20933989 is an equidigital number, since it uses as much as digits as its factorization.

20933989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 104976, while the sum is 43.

The square root of 20933989 is about 4575.3676355021. The cubic root of 20933989 is about 275.6030358901.

The spelling of 20933989 in words is "twenty million, nine hundred thirty-three thousand, nine hundred eighty-nine".