20989693 has 8 divisors (see below), whose sum is σ = 21881312. Its totient is φ = 20115216.

The previous prime is 20989651. The next prime is 20989711. The reversal of 20989693 is 39698902.

It is a happy number.

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 20989693 - 2²¹ = 18892541 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20989603) 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, 1755 + ... + 6712.

It is an arithmetic number, because the mean of its divisors is an integer number (2735164).

Almost surely, 2^20989693 is an apocalyptic number.

It is an amenable number.

20989693 is a deficient number, since it is larger than the sum of its proper divisors (891619).

20989693 is an equidigital number, since it uses as much as digits as its factorization.

20989693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8571.

The product of its (nonzero) digits is 209952, while the sum is 46.

The square root of 20989693 is about 4581.4509710353. The cubic root of 20989693 is about 275.8472733762.

The spelling of 20989693 in words is "twenty million, nine hundred eighty-nine thousand, six hundred ninety-three".