21428608277 has 2 divisors, whose sum is σ = 21428608278. Its totient is φ = 21428608276.

The previous prime is 21428608241. The next prime is 21428608319. The reversal of 21428608277 is 77280682412.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18419646961 + 3008961316 = 135719^2 + 54854^2 .

It is a cyclic number.

It is not a de Polignac number, because 21428608277 - 2⁸ = 21428608021 is a prime.

It is a super-3 number, since 3×21428608277³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21428608207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10714304138 + 10714304139.

It is an arithmetic number, because the mean of its divisors is an integer number (10714304139).

Almost surely, 2^21428608277 is an apocalyptic number.

It is an amenable number.

21428608277 is a deficient number, since it is larger than the sum of its proper divisors (1).

21428608277 is an equidigital number, since it uses as much as digits as its factorization.

21428608277 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 602112, while the sum is 47.

The spelling of 21428608277 in words is "twenty-one billion, four hundred twenty-eight million, six hundred eight thousand, two hundred seventy-seven".