20428872 has 16 divisors (see below), whose sum is σ = 51072240. Its totient is φ = 6809616.

The previous prime is 20428843. The next prime is 20428909. The reversal of 20428872 is 27882402.

It is a super-2 number, since 2×20428872² = 834677622384768, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 425578 + ... + 425625.

It is an arithmetic number, because the mean of its divisors is an integer number (3192015).

Almost surely, 2^20428872 is an apocalyptic number.

It is an amenable number.

20428872 is an abundant number, since it is smaller than the sum of its proper divisors (30643368).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20428872 is a wasteful number, since it uses less digits than its factorization.

20428872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 851212 (or 851208 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 33.

The square root of 20428872 is about 4519.8309702908. The cubic root of 20428872 is about 273.3682855693.

The spelling of 20428872 in words is "twenty million, four hundred twenty-eight thousand, eight hundred seventy-two".