21020620277 has 2 divisors, whose sum is σ = 21020620278. Its totient is φ = 21020620276.

The previous prime is 21020620249. The next prime is 21020620321. The reversal of 21020620277 is 77202602012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13584834916 + 7435785361 = 116554^2 + 86231^2 .

It is a cyclic number.

It is not a de Polignac number, because 21020620277 - 2⁸ = 21020620021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21020620237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510310138 + 10510310139.

It is an arithmetic number, because the mean of its divisors is an integer number (10510310139).

Almost surely, 2^21020620277 is an apocalyptic number.

It is an amenable number.

21020620277 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020620277 is an equidigital number, since it uses as much as digits as its factorization.

21020620277 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4704, while the sum is 29.

The spelling of 21020620277 in words is "twenty-one billion, twenty million, six hundred twenty thousand, two hundred seventy-seven".