21377202577 has 2 divisors, whose sum is σ = 21377202578. Its totient is φ = 21377202576.

The previous prime is 21377202541. The next prime is 21377202629. The reversal of 21377202577 is 77520277312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21258806416 + 118396161 = 145804^2 + 10881^2 .

It is a cyclic number.

It is not a de Polignac number, because 21377202577 - 2¹¹ = 21377200529 is a prime.

It is not a weakly prime, because it can be changed into another prime (21377202377) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10688601288 + 10688601289.

It is an arithmetic number, because the mean of its divisors is an integer number (10688601289).

Almost surely, 2^21377202577 is an apocalyptic number.

It is an amenable number.

21377202577 is a deficient number, since it is larger than the sum of its proper divisors (1).

21377202577 is an equidigital number, since it uses as much as digits as its factorization.

21377202577 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288120, while the sum is 43.

Adding to 21377202577 its reverse (77520277312), we get a palindrome (98897479889).

The spelling of 21377202577 in words is "twenty-one billion, three hundred seventy-seven million, two hundred two thousand, five hundred seventy-seven".