20109428 has 6 divisors (see below), whose sum is σ = 35191506. Its totient is φ = 10054712.

The previous prime is 20109413. The next prime is 20109431. The reversal of 20109428 is 82490102.

It can be written as a sum of positive squares in only one way, i.e., 15665764 + 4443664 = 3958^2 + 2108^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20109397 and 20109406.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2513675 + ... + 2513682.

It is an arithmetic number, because the mean of its divisors is an integer number (5865251).

Almost surely, 2^20109428 is an apocalyptic number.

It is an amenable number.

20109428 is a deficient number, since it is larger than the sum of its proper divisors (15082078).

20109428 is a wasteful number, since it uses less digits than its factorization.

20109428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5027361 (or 5027359 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 20109428 is about 4484.3536881027. The cubic root of 20109428 is about 271.9359169967.

The spelling of 20109428 in words is "twenty million, one hundred nine thousand, four hundred twenty-eight".