21631283 has 2 divisors, whose sum is σ = 21631284. Its totient is φ = 21631282.

The previous prime is 21631243. The next prime is 21631289. The reversal of 21631283 is 38213612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21631283 - 2¹⁴ = 21614899 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21631289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10815641 + 10815642.

It is an arithmetic number, because the mean of its divisors is an integer number (10815642).

Almost surely, 2^21631283 is an apocalyptic number.

21631283 is a deficient number, since it is larger than the sum of its proper divisors (1).

21631283 is an equidigital number, since it uses as much as digits as its factorization.

21631283 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 26.

The square root of 21631283 is about 4650.9443127176. The cubic root of 21631283 is about 278.6297122217.

Adding to 21631283 its reverse (38213612), we get a palindrome (59844895).

The spelling of 21631283 in words is "twenty-one million, six hundred thirty-one thousand, two hundred eighty-three".