20779989 has 8 divisors (see below), whose sum is σ = 28382592. Its totient is φ = 13515360.

The previous prime is 20779973. The next prime is 20780003. The reversal of 20779989 is 98997702.

It is a happy number.

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

It is not a de Polignac number, because 20779989 - 2⁴ = 20779973 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20779919) 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, 84349 + ... + 84594.

It is an arithmetic number, because the mean of its divisors is an integer number (3547824).

Almost surely, 2^20779989 is an apocalyptic number.

It is an amenable number.

20779989 is a deficient number, since it is larger than the sum of its proper divisors (7602603).

20779989 is a wasteful number, since it uses less digits than its factorization.

20779989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168987.

The product of its (nonzero) digits is 571536, while the sum is 51.

The square root of 20779989 is about 4558.5073214815. The cubic root of 20779989 is about 274.9255511967.

The spelling of 20779989 in words is "twenty million, seven hundred seventy-nine thousand, nine hundred eighty-nine".