21251201 has 2 divisors, whose sum is σ = 21251202. Its totient is φ = 21251200.

The previous prime is 21251179. The next prime is 21251239. The reversal of 21251201 is 10215212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10857025 + 10394176 = 3295^2 + 3224^2 .

It is a cyclic number.

It is not a de Polignac number, because 21251201 - 2⁶ = 21251137 is a prime.

It is a super-2 number, since 2×21251201² = 903227087884802, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21251281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10625600 + 10625601.

It is an arithmetic number, because the mean of its divisors is an integer number (10625601).

Almost surely, 2^21251201 is an apocalyptic number.

It is an amenable number.

21251201 is a deficient number, since it is larger than the sum of its proper divisors (1).

21251201 is an equidigital number, since it uses as much as digits as its factorization.

21251201 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40, while the sum is 14.

The square root of 21251201 is about 4609.9024935458. The cubic root of 21251201 is about 276.9881308803.

Adding to 21251201 its reverse (10215212), we get a palindrome (31466413).

The spelling of 21251201 in words is "twenty-one million, two hundred fifty-one thousand, two hundred one".