20428779 has 8 divisors (see below), whose sum is σ = 31129600. Its totient is φ = 11673576.

The previous prime is 20428777. The next prime is 20428799. The reversal of 20428779 is 97782402.

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

It is not a de Polignac number, because 20428779 - 2¹ = 20428777 is a prime.

It is a super-2 number, since 2×20428779² = 834670022861682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20428777) 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, 486379 + ... + 486420.

It is an arithmetic number, because the mean of its divisors is an integer number (3891200).

Almost surely, 2^20428779 is an apocalyptic number.

20428779 is a deficient number, since it is larger than the sum of its proper divisors (10700821).

20428779 is an equidigital number, since it uses as much as digits as its factorization.

20428779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 972809.

The product of its (nonzero) digits is 56448, while the sum is 39.

The square root of 20428779 is about 4519.8206822838. The cubic root of 20428779 is about 273.3678707432.

The spelling of 20428779 in words is "twenty million, four hundred twenty-eight thousand, seven hundred seventy-nine".