21201031 has 2 divisors, whose sum is σ = 21201032. Its totient is φ = 21201030.

The previous prime is 21200987. The next prime is 21201041. The reversal of 21201031 is 13010212.

It is an a-pointer prime, because the next prime (21201041) can be obtained adding 21201031 to its sum of digits (10).

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21201031 - 2¹³ = 21192839 is a prime.

It is a super-2 number, since 2×21201031² = 898967430925922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21200999 and 21201017.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21201041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600515 + 10600516.

It is an arithmetic number, because the mean of its divisors is an integer number (10600516).

Almost surely, 2^21201031 is an apocalyptic number.

21201031 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201031 is an equidigital number, since it uses as much as digits as its factorization.

21201031 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 21201031 is about 4604.4577313729. The cubic root of 21201031 is about 276.7699872164.

Adding to 21201031 its reverse (13010212), we get a palindrome (34211243).

The spelling of 21201031 in words is "twenty-one million, two hundred one thousand, thirty-one".