20516989 has 8 divisors (see below), whose sum is σ = 21814272. Its totient is φ = 19253520.

The previous prime is 20516953. The next prime is 20516999. The reversal of 20516989 is 98961502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20516989 - 2⁷ = 20516861 is a prime.

It is a super-2 number, since 2×20516989² = 841893675252242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20516939) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7197 + ... + 9634.

It is an arithmetic number, because the mean of its divisors is an integer number (2726784).

Almost surely, 2^20516989 is an apocalyptic number.

It is an amenable number.

20516989 is a deficient number, since it is larger than the sum of its proper divisors (1297283).

20516989 is a wasteful number, since it uses less digits than its factorization.

20516989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16907.

The product of its (nonzero) digits is 38880, while the sum is 40.

The square root of 20516989 is about 4529.5683017259. The cubic root of 20516989 is about 273.7607667276.

The spelling of 20516989 in words is "twenty million, five hundred sixteen thousand, nine hundred eighty-nine".