20828056221 has 12 divisors (see below), whose sum is σ = 34382823072. Its totient is φ = 11901746376.

The previous prime is 20828056219. The next prime is 20828056241. The reversal of 20828056221 is 12265082802.

20828056221 is a `hidden beast` number, since 2 + 0 + 8 + 28 + 0 + 5 + 622 + 1 = 666.

It is not a de Polignac number, because 20828056221 - 2¹ = 20828056219 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20828056241) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 165301971 + ... + 165302096.

It is an arithmetic number, because the mean of its divisors is an integer number (2865235256).

Almost surely, 2^20828056221 is an apocalyptic number.

20828056221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20828056221 is a deficient number, since it is larger than the sum of its proper divisors (13554766851).

20828056221 is a wasteful number, since it uses less digits than its factorization.

20828056221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330604080 (or 330604077 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 36.

The spelling of 20828056221 in words is "twenty billion, eight hundred twenty-eight million, fifty-six thousand, two hundred twenty-one".