20728042 has 16 divisors (see below), whose sum is σ = 32146632. Its totient is φ = 10017280.

The previous prime is 20728033. The next prime is 20728061. The reversal of 20728042 is 24082702.

It can be written as a sum of positive squares in 4 ways, for example, as 9174841 + 11553201 = 3029^2 + 3399^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20727998 and 20728016.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8148 + ... + 10384.

Almost surely, 2^20728042 is an apocalyptic number.

20728042 is a deficient number, since it is larger than the sum of its proper divisors (11418590).

20728042 is a wasteful number, since it uses less digits than its factorization.

20728042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2393.

The product of its (nonzero) digits is 1792, while the sum is 25.

The square root of 20728042 is about 4552.8059479842. The cubic root of 20728042 is about 274.6962685155.

The spelling of 20728042 in words is "twenty million, seven hundred twenty-eight thousand, forty-two".