20428249 has 4 divisors (see below), whose sum is σ = 21503440. Its totient is φ = 19353060.

The previous prime is 20428241. The next prime is 20428273. The reversal of 20428249 is 94282402.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20428249 - 2³ = 20428241 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20428249.

It is not an unprimeable number, because it can be changed into a prime (20428241) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 537567 + ... + 537604.

It is an arithmetic number, because the mean of its divisors is an integer number (5375860).

Almost surely, 2^20428249 is an apocalyptic number.

It is an amenable number.

20428249 is a deficient number, since it is larger than the sum of its proper divisors (1075191).

20428249 is a wasteful number, since it uses less digits than its factorization.

20428249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1075190.

The product of its (nonzero) digits is 9216, while the sum is 31.

The square root of 20428249 is about 4519.7620512589. The cubic root of 20428249 is about 273.3655066563.

The spelling of 20428249 in words is "twenty million, four hundred twenty-eight thousand, two hundred forty-nine".