20328781 has 8 divisors (see below), whose sum is σ = 22213728. Its totient is φ = 18450000.

The previous prime is 20328779. The next prime is 20328793. The reversal of 20328781 is 18782302.

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 20328781 - 2¹ = 20328779 is a prime.

It is a super-2 number, since 2×20328781² = 826518673891922, 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 (20328701) 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, 7906 + ... + 10156.

It is an arithmetic number, because the mean of its divisors is an integer number (2776716).

Almost surely, 2^20328781 is an apocalyptic number.

It is an amenable number.

20328781 is a deficient number, since it is larger than the sum of its proper divisors (1884947).

20328781 is a wasteful number, since it uses less digits than its factorization.

20328781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3083.

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 20328781 is about 4508.7449473218. The cubic root of 20328781 is about 272.9210996256.

The spelling of 20328781 in words is "twenty million, three hundred twenty-eight thousand, seven hundred eighty-one".