21371377 has 2 divisors, whose sum is σ = 21371378. Its totient is φ = 21371376.

The previous prime is 21371359. The next prime is 21371401. The reversal of 21371377 is 77317312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20875761 + 495616 = 4569^2 + 704^2 .

It is a cyclic number.

It is not a de Polignac number, because 21371377 - 2¹¹ = 21369329 is a prime.

It is a super-2 number, since 2×21371377² = 913471509752258, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21371177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10685688 + 10685689.

It is an arithmetic number, because the mean of its divisors is an integer number (10685689).

Almost surely, 2^21371377 is an apocalyptic number.

It is an amenable number.

21371377 is a deficient number, since it is larger than the sum of its proper divisors (1).

21371377 is an equidigital number, since it uses as much as digits as its factorization.

21371377 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6174, while the sum is 31.

The square root of 21371377 is about 4622.9186668165. The cubic root of 21371377 is about 277.5092743701.

Adding to 21371377 its reverse (77317312), we get a palindrome (98688689).

The spelling of 21371377 in words is "twenty-one million, three hundred seventy-one thousand, three hundred seventy-seven".