20428989 has 16 divisors (see below), whose sum is σ = 31234560. Its totient is φ = 11634480.

The previous prime is 20428987. The next prime is 20429011. The reversal of 20428989 is 98982402.

It is not a de Polignac number, because 20428989 - 2¹ = 20428987 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20428989.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20428987) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5482 + ... + 8420.

It is an arithmetic number, because the mean of its divisors is an integer number (1952160).

Almost surely, 2^20428989 is an apocalyptic number.

It is an amenable number.

20428989 is a deficient number, since it is larger than the sum of its proper divisors (10805571).

20428989 is a wasteful number, since it uses less digits than its factorization.

20428989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3280.

The product of its (nonzero) digits is 82944, while the sum is 42.

The square root of 20428989 is about 4519.8439132342. The cubic root of 20428989 is about 273.3688074456.

The spelling of 20428989 in words is "twenty million, four hundred twenty-eight thousand, nine hundred eighty-nine".