21261259 has 2 divisors, whose sum is σ = 21261260. Its totient is φ = 21261258.

The previous prime is 21261241. The next prime is 21261277. The reversal of 21261259 is 95216212.

It is a balanced prime because it is at equal distance from previous prime (21261241) and next prime (21261277).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21261259 is a prime.

It is a super-2 number, since 2×21261259² = 904082268530162, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21261239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10630629 + 10630630.

It is an arithmetic number, because the mean of its divisors is an integer number (10630630).

Almost surely, 2^21261259 is an apocalyptic number.

21261259 is a deficient number, since it is larger than the sum of its proper divisors (1).

21261259 is an equidigital number, since it uses as much as digits as its factorization.

21261259 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2160, while the sum is 28.

The square root of 21261259 is about 4610.9932769415. The cubic root of 21261259 is about 277.0318226417.

The spelling of 21261259 in words is "twenty-one million, two hundred sixty-one thousand, two hundred fifty-nine".