20517899428 has 12 divisors (see below), whose sum is σ = 38668349020. Its totient is φ = 9469799712.

The previous prime is 20517899407. The next prime is 20517899431. The reversal of 20517899428 is 82499871502.

It can be written as a sum of positive squares in 2 ways, for example, as 11415212964 + 9102686464 = 106842^2 + 95408^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 197287443 + ... + 197287546.

Almost surely, 2^20517899428 is an apocalyptic number.

It is an amenable number.

20517899428 is a deficient number, since it is larger than the sum of its proper divisors (18150449592).

20517899428 is a wasteful number, since it uses less digits than its factorization.

20517899428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 394575006 (or 394575004 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 55.

The spelling of 20517899428 in words is "twenty billion, five hundred seventeen million, eight hundred ninety-nine thousand, four hundred twenty-eight".