21301031 has 2 divisors, whose sum is σ = 21301032. Its totient is φ = 21301030.

The previous prime is 21300997. The next prime is 21301043. The reversal of 21301031 is 13010312.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21301031 is a prime.

It is a super-2 number, since 2×21301031² = 907467843325922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21301081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10650515 + 10650516.

It is an arithmetic number, because the mean of its divisors is an integer number (10650516).

Almost surely, 2^21301031 is an apocalyptic number.

21301031 is a deficient number, since it is larger than the sum of its proper divisors (1).

21301031 is an equidigital number, since it uses as much as digits as its factorization.

21301031 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18, while the sum is 11.

The square root of 21301031 is about 4615.3039986549. The cubic root of 21301031 is about 277.2044566095.

Adding to 21301031 its reverse (13010312), we get a palindrome (34311343).

It can be divided in two parts, 2 and 1301031, that multiplied together give a palindrome (2602062).

The spelling of 21301031 in words is "twenty-one million, three hundred one thousand, thirty-one".